diff --git a/tests/unit/domain/test_plan_generator_utils.py b/tests/unit/domain/test_plan_generator_utils.py
new file mode 100755
index 000000000..23106c8d5
--- /dev/null
+++ b/tests/unit/domain/test_plan_generator_utils.py
@@ -0,0 +1,537 @@
+"""plan_generator_utils 单元测试 - wave166
+
+覆盖：
+- distribute_assets 素材分配（4种模式 + 边界）
+- map_clip_types_for_mode clip类型映射（4种模式）
+- generate_default_clips 默认片段生成（4种模式 + 边界）
+- create_clips_from_configs 从模板配置创建
+"""
+
+import pytest
+
+from packages.domain.edit_plan_clip import EditPlanClip
+from packages.domain.editing_mode import EditingMode
+from packages.domain.plan_generator_utils import (
+    DEFAULT_CLIP_DURATION,
+    create_clips_from_configs,
+    distribute_assets,
+    generate_default_clips,
+    map_clip_types_for_mode,
+)
+from packages.domain.template_clip_config import ClipType, TemplateClipConfig
+
+# ============================================================
+# 辅助函数
+# ============================================================
+
+
+def _make_main_clip(plan_id: str, order: int = 0) -> EditPlanClip:
+    return EditPlanClip.create(
+        plan_id=plan_id,
+        clip_type=ClipType.MAIN.value,
+        order=order,
+        duration=5.0,
+    )
+
+
+def _make_clips(plan_id: str, count: int, clip_type: str = "main") -> list[EditPlanClip]:
+    return [
+        EditPlanClip.create(
+            plan_id=plan_id,
+            clip_type=clip_type,
+            order=i,
+            duration=5.0,
+        )
+        for i in range(count)
+    ]
+
+
+# ============================================================
+# distribute_assets - ONE_TAKE
+# ============================================================
+
+
+class TestDistributeOneTake:
+    def test_equal_count(self):
+        clips = _make_clips("p1", 3)
+        assets = ["a1", "a2", "a3"]
+        distribute_assets(clips, assets, EditingMode.ONE_TAKE.value)
+        assert clips[0].asset_id == "a1"
+        assert clips[1].asset_id == "a2"
+        assert clips[2].asset_id == "a3"
+
+    def test_more_clips_than_assets(self):
+        clips = _make_clips("p1", 5)
+        assets = ["a1", "a2"]
+        distribute_assets(clips, assets, EditingMode.ONE_TAKE.value)
+        assert clips[0].asset_id == "a1"
+        assert clips[1].asset_id == "a2"
+        assert clips[2].asset_id == ""  # 没分配到
+
+    def test_more_assets_than_clips(self):
+        clips = _make_clips("p1", 2)
+        assets = ["a1", "a2", "a3"]
+        distribute_assets(clips, assets, EditingMode.ONE_TAKE.value)
+        assert clips[0].asset_id == "a1"
+        assert clips[1].asset_id == "a2"
+
+    def test_empty_assets(self):
+        clips = _make_clips("p1", 3)
+        distribute_assets(clips, [], EditingMode.ONE_TAKE.value)
+        for c in clips:
+            assert c.asset_id == ""
+
+    def test_empty_clips(self):
+        # 不报错即可
+        distribute_assets([], ["a1", "a2"], EditingMode.ONE_TAKE.value)
+
+    def test_only_main_clips_get_assigned(self):
+        # intro/outro 不应该被分配
+        clips = []
+        clips.append(EditPlanClip.create("p1", clip_type="intro", order=0, duration=3.0))
+        clips.append(_make_main_clip("p1", order=1))
+        clips.append(EditPlanClip.create("p1", clip_type="outro", order=2, duration=3.0))
+        assets = ["a1"]
+        distribute_assets(clips, assets, EditingMode.ONE_TAKE.value)
+        assert clips[0].asset_id == ""  # intro 无
+        assert clips[1].asset_id == "a1"  # main 有
+        assert clips[2].asset_id == ""  # outro 无
+
+
+# ============================================================
+# distribute_assets - PIP
+# ============================================================
+
+
+class TestDistributePip:
+    def test_first_asset_to_main(self):
+        clips = _make_clips("p1", 3)
+        # 第一个main是背景，其余改为overlay
+        map_clip_types_for_mode(clips, EditingMode.PIP.value)
+        assets = ["a1", "a2", "a3"]
+        distribute_assets(clips, assets, EditingMode.PIP.value)
+        assert clips[0].asset_id == "a1"  # main → 背景
+        assert clips[1].asset_id == "a2"  # overlay
+        assert clips[2].asset_id == "a3"  # overlay
+
+    def test_single_asset(self):
+        clips = _make_clips("p1", 1)
+        map_clip_types_for_mode(clips, EditingMode.PIP.value)
+        assets = ["a1"]
+        distribute_assets(clips, assets, EditingMode.PIP.value)
+        assert clips[0].asset_id == "a1"
+
+    def test_only_main_clip_with_no_overlays(self):
+        clips = _make_clips("p1", 1)
+        map_clip_types_for_mode(clips, EditingMode.PIP.value)
+        assets = ["a1", "a2", "a3"]  # 多余素材
+        distribute_assets(clips, assets, EditingMode.PIP.value)
+        assert clips[0].asset_id == "a1"
+
+
+# ============================================================
+# distribute_assets - VOICE_OVER
+# ============================================================
+
+
+class TestDistributeVoiceOver:
+    def test_assets_to_main_clips(self):
+        clips = _make_clips("p1", 3)
+        assets = ["a1", "a2", "a3"]
+        distribute_assets(clips, assets, EditingMode.VOICE_OVER.value)
+        assert clips[0].asset_id == "a1"
+        assert clips[1].asset_id == "a2"
+        assert clips[2].asset_id == "a3"
+
+    def test_more_clips_than_assets(self):
+        clips = _make_clips("p1", 5)
+        assets = ["a1", "a2"]
+        distribute_assets(clips, assets, EditingMode.VOICE_OVER.value)
+        assert clips[0].asset_id == "a1"
+        assert clips[1].asset_id == "a2"
+        assert clips[2].asset_id == ""
+
+
+# ============================================================
+# distribute_assets - VOICE_PIP
+# ============================================================
+
+
+class TestDistributeVoicePip:
+    def test_three_assets_three_roles(self):
+        clips = _make_clips("p1", 3)
+        map_clip_types_for_mode(clips, EditingMode.VOICE_PIP.value)
+        assets = ["a1", "a2", "a3"]
+        distribute_assets(clips, assets, EditingMode.VOICE_PIP.value)
+        assert clips[0].clip_type == "background"
+        assert clips[0].asset_id == "a1"
+        assert clips[1].clip_type == "corner_voice"
+        assert clips[1].asset_id == "a2"
+        assert clips[2].clip_type == "b_roll"
+        assert clips[2].asset_id == "a3"
+
+    def test_single_asset(self):
+        clips = _make_clips("p1", 1)
+        map_clip_types_for_mode(clips, EditingMode.VOICE_PIP.value)
+        assets = ["a1"]
+        distribute_assets(clips, assets, EditingMode.VOICE_PIP.value)
+        assert clips[0].clip_type == "background"
+        assert clips[0].asset_id == "a1"
+
+    def test_two_assets(self):
+        clips = _make_clips("p1", 2)
+        map_clip_types_for_mode(clips, EditingMode.VOICE_PIP.value)
+        assets = ["a1", "a2"]
+        distribute_assets(clips, assets, EditingMode.VOICE_PIP.value)
+        assert clips[0].asset_id == "a1"
+        assert clips[1].asset_id == "a2"
+
+
+# ============================================================
+# distribute_assets - 边界情况
+# ============================================================
+
+
+class TestDistributeEdgeCases:
+    def test_unknown_mode_falls_back_to_one_take(self):
+        clips = _make_clips("p1", 2)
+        assets = ["a1", "a2"]
+        distribute_assets(clips, assets, "unknown_mode")
+        assert clips[0].asset_id == "a1"
+        assert clips[1].asset_id == "a2"
+
+    def test_none_clips_no_crash(self):
+        # 空列表
+        distribute_assets([], ["a1"], EditingMode.ONE_TAKE.value)
+
+    def test_none_assets_no_crash(self):
+        clips = _make_clips("p1", 2)
+        distribute_assets(clips, [], EditingMode.ONE_TAKE.value)
+        for c in clips:
+            assert c.asset_id == ""
+
+
+# ============================================================
+# map_clip_types_for_mode
+# ============================================================
+
+
+class TestMapClipTypesForMode:
+    def test_one_take_unchanged(self):
+        clips = _make_clips("p1", 3)
+        original_types = [c.clip_type for c in clips]
+        map_clip_types_for_mode(clips, EditingMode.ONE_TAKE.value)
+        assert [c.clip_type for c in clips] == original_types
+
+    def test_voice_over_unchanged(self):
+        clips = _make_clips("p1", 3)
+        map_clip_types_for_mode(clips, EditingMode.VOICE_OVER.value)
+        for c in clips:
+            assert c.clip_type == ClipType.MAIN.value
+
+    def test_pip_first_stays_main_rest_overlay(self):
+        clips = _make_clips("p1", 4)
+        map_clip_types_for_mode(clips, EditingMode.PIP.value)
+        assert clips[0].clip_type == ClipType.MAIN.value
+        assert clips[1].clip_type == "overlay"
+        assert clips[2].clip_type == "overlay"
+        assert clips[3].clip_type == "overlay"
+
+    def test_pip_single_clip_stays_main(self):
+        clips = _make_clips("p1", 1)
+        map_clip_types_for_mode(clips, EditingMode.PIP.value)
+        assert clips[0].clip_type == ClipType.MAIN.value
+
+    def test_voice_pip_mapping(self):
+        clips = _make_clips("p1", 5)
+        map_clip_types_for_mode(clips, EditingMode.VOICE_PIP.value)
+        assert clips[0].clip_type == "background"
+        assert clips[1].clip_type == "corner_voice"
+        assert clips[2].clip_type == "b_roll"
+        assert clips[3].clip_type == "b_roll"
+        assert clips[4].clip_type == "b_roll"
+
+    def test_voice_pip_two_clips(self):
+        clips = _make_clips("p1", 2)
+        map_clip_types_for_mode(clips, EditingMode.VOICE_PIP.value)
+        assert clips[0].clip_type == "background"
+        assert clips[1].clip_type == "corner_voice"
+
+    def test_voice_pip_single_clip(self):
+        clips = _make_clips("p1", 1)
+        map_clip_types_for_mode(clips, EditingMode.VOICE_PIP.value)
+        assert clips[0].clip_type == "background"
+
+    def test_non_main_clips_unchanged(self):
+        clips = [
+            EditPlanClip.create("p1", clip_type="intro", order=0, duration=3.0),
+            _make_main_clip("p1", order=1),
+            EditPlanClip.create("p1", clip_type="outro", order=2, duration=3.0),
+        ]
+        map_clip_types_for_mode(clips, EditingMode.VOICE_PIP.value)
+        assert clips[0].clip_type == "intro"
+        assert clips[1].clip_type == "background"  # main 被改了
+        assert clips[2].clip_type == "outro"
+
+    def test_empty_clips_no_error(self):
+        map_clip_types_for_mode([], EditingMode.PIP.value)
+
+    def test_no_main_clips_no_error(self):
+        clips = [
+            EditPlanClip.create("p1", clip_type="intro", order=0, duration=3.0),
+        ]
+        map_clip_types_for_mode(clips, EditingMode.PIP.value)
+        assert clips[0].clip_type == "intro"
+
+
+# ============================================================
+# generate_default_clips
+# ============================================================
+
+
+class TestGenerateDefaultClipsOneTake:
+    def test_basic(self):
+        clips = generate_default_clips("p1", EditingMode.ONE_TAKE.value, 3)
+        assert len(clips) == 3
+        for c in clips:
+            assert c.clip_type == ClipType.MAIN.value
+            assert c.plan_id == "p1"
+
+    def test_order_sequential(self):
+        clips = generate_default_clips("p1", EditingMode.ONE_TAKE.value, 5)
+        for i, c in enumerate(clips):
+            assert c.order == i
+
+    def test_zero_assets_at_least_one(self):
+        clips = generate_default_clips("p1", EditingMode.ONE_TAKE.value, 0)
+        assert len(clips) == 1
+
+    def test_negative_assets_at_least_one(self):
+        clips = generate_default_clips("p1", EditingMode.ONE_TAKE.value, -5)
+        assert len(clips) == 1
+
+    def test_default_duration(self):
+        clips = generate_default_clips("p1", EditingMode.ONE_TAKE.value, 1)
+        assert clips[0].duration == DEFAULT_CLIP_DURATION
+
+
+class TestGenerateDefaultClipsPip:
+    def test_one_asset(self):
+        clips = generate_default_clips("p1", EditingMode.PIP.value, 1)
+        assert len(clips) == 1
+        assert clips[0].clip_type == ClipType.MAIN.value
+
+    def test_three_assets(self):
+        clips = generate_default_clips("p1", EditingMode.PIP.value, 3)
+        assert len(clips) == 3
+        assert clips[0].clip_type == ClipType.MAIN.value
+        assert clips[1].clip_type == "overlay"
+        assert clips[2].clip_type == "overlay"
+
+    def test_zero_assets(self):
+        clips = generate_default_clips("p1", EditingMode.PIP.value, 0)
+        assert len(clips) >= 1
+        assert clips[0].clip_type == ClipType.MAIN.value
+
+
+class TestGenerateDefaultClipsVoiceOver:
+    def test_basic(self):
+        clips = generate_default_clips("p1", EditingMode.VOICE_OVER.value, 3)
+        assert len(clips) == 3
+        for c in clips:
+            assert c.clip_type == ClipType.MAIN.value
+
+    def test_has_b_roll_config(self):
+        clips = generate_default_clips("p1", EditingMode.VOICE_OVER.value, 2)
+        # VOICE_OVER 标记 role=b_roll
+        assert clips[0].config.get("role") == "b_roll"
+
+
+class TestGenerateDefaultClipsVoicePip:
+    def test_one_asset(self):
+        clips = generate_default_clips("p1", EditingMode.VOICE_PIP.value, 1)
+        assert len(clips) == 1
+        assert clips[0].clip_type == "background"
+
+    def test_two_assets(self):
+        clips = generate_default_clips("p1", EditingMode.VOICE_PIP.value, 2)
+        assert len(clips) == 2
+        assert clips[0].clip_type == "background"
+        assert clips[1].clip_type == "corner_voice"
+
+    def test_five_assets(self):
+        clips = generate_default_clips("p1", EditingMode.VOICE_PIP.value, 5)
+        assert len(clips) == 5
+        assert clips[0].clip_type == "background"
+        assert clips[1].clip_type == "corner_voice"
+        assert clips[2].clip_type == "b_roll"
+        assert clips[3].clip_type == "b_roll"
+        assert clips[4].clip_type == "b_roll"
+
+    def test_zero_assets(self):
+        clips = generate_default_clips("p1", EditingMode.VOICE_PIP.value, 0)
+        assert len(clips) >= 1
+        assert clips[0].clip_type == "background"
+
+
+class TestGenerateDefaultClipsUnknownMode:
+    def test_falls_back_to_one_take(self):
+        clips = generate_default_clips("p1", "unknown_mode", 3)
+        assert len(clips) == 3
+        for c in clips:
+            assert c.clip_type == ClipType.MAIN.value
+
+
+# ============================================================
+# create_clips_from_configs
+# ============================================================
+
+
+def _make_template_config(
+    cfg_id: str,
+    order: int,
+    clip_type: ClipType = ClipType.MAIN,
+    min_dur: float = 0,
+    max_dur: float = 0,
+) -> TemplateClipConfig:
+    return TemplateClipConfig(
+        id=cfg_id,
+        template_id="t1",
+        clip_type=clip_type,
+        order=order,
+        min_duration=min_dur,
+        max_duration=max_dur,
+        transition_effect="cut",
+        config={},
+    )
+
+
+class TestCreateClipsFromConfigs:
+    def test_empty_configs(self):
+        result = create_clips_from_configs("p1", [])
+        assert result == []
+
+    def test_single_config(self):
+        configs = [_make_template_config("c1", 0, min_dur=3.0, max_dur=7.0)]
+        result = create_clips_from_configs("p1", configs)
+        assert len(result) == 1
+        assert result[0].plan_id == "p1"
+        assert result[0].template_clip_config_id == "c1"
+        # 平均时长 = (3+7)/2 = 5.0
+        assert result[0].duration == pytest.approx(5.0)
+
+    def test_duration_min_only(self):
+        configs = [_make_template_config("c1", 0, min_dur=4.0)]
+        result = create_clips_from_configs("p1", configs)
+        assert result[0].duration == 4.0
+
+    def test_duration_max_only(self):
+        configs = [_make_template_config("c1", 0, max_dur=6.0)]
+        result = create_clips_from_configs("p1", configs)
+        assert result[0].duration == 6.0
+
+    def test_duration_default_when_no_bounds(self):
+        configs = [_make_template_config("c1", 0)]
+        result = create_clips_from_configs("p1", configs)
+        assert result[0].duration == DEFAULT_CLIP_DURATION
+
+    def test_sorted_by_order(self):
+        configs = [
+            _make_template_config("c_third", 2),
+            _make_template_config("c_first", 0),
+            _make_template_config("c_second", 1),
+        ]
+        result = create_clips_from_configs("p1", configs)
+        assert len(result) == 3
+        assert result[0].template_clip_config_id == "c_first"
+        assert result[1].template_clip_config_id == "c_second"
+        assert result[2].template_clip_config_id == "c_third"
+        assert result[0].order == 0
+        assert result[1].order == 1
+        assert result[2].order == 2
+
+    def test_clip_type_preserved(self):
+        configs = [
+            TemplateClipConfig(
+                id="c_intro",
+                template_id="t1",
+                clip_type=ClipType.INTRO,
+                order=0,
+                min_duration=3.0,
+                max_duration=3.0,
+                transition_effect="cut",
+                config={},
+            ),
+            TemplateClipConfig(
+                id="c_main",
+                template_id="t1",
+                clip_type=ClipType.MAIN,
+                order=1,
+                min_duration=5.0,
+                max_duration=5.0,
+                transition_effect="cut",
+                config={},
+            ),
+        ]
+        result = create_clips_from_configs("p1", configs)
+        assert result[0].clip_type == ClipType.INTRO.value
+        assert result[1].clip_type == ClipType.MAIN.value
+
+    def test_playback_speed_from_config(self):
+        configs = [
+            TemplateClipConfig(
+                id="c1",
+                template_id="t1",
+                clip_type=ClipType.MAIN,
+                order=0,
+                min_duration=5.0,
+                max_duration=5.0,
+                transition_effect="cut",
+                config={"playback_speed": 1.5},
+            )
+        ]
+        result = create_clips_from_configs("p1", configs)
+        assert result[0].playback_speed == pytest.approx(1.5)
+
+    def test_speed_ratio_fallback(self):
+        # 兼容 speed_ratio 字段名
+        configs = [
+            TemplateClipConfig(
+                id="c1",
+                template_id="t1",
+                clip_type=ClipType.MAIN,
+                order=0,
+                min_duration=5.0,
+                max_duration=5.0,
+                transition_effect="cut",
+                config={"speed_ratio": 0.8},
+            )
+        ]
+        result = create_clips_from_configs("p1", configs)
+        assert result[0].playback_speed == pytest.approx(0.8)
+
+    def test_default_playback_speed(self):
+        configs = [_make_template_config("c1", 0, min_dur=5.0, max_dur=5.0)]
+        result = create_clips_from_configs("p1", configs)
+        assert result[0].playback_speed == pytest.approx(1.0)
+
+    def test_transition_effect_preserved(self):
+        configs = [
+            TemplateClipConfig(
+                id="c1",
+                template_id="t1",
+                clip_type=ClipType.MAIN,
+                order=0,
+                min_duration=5.0,
+                max_duration=5.0,
+                transition_effect="fade",
+                config={},
+            )
+        ]
+        result = create_clips_from_configs("p1", configs)
+        assert result[0].transition_effect == "fade"
+
+    def test_returns_edit_plan_clip_objects(self):
+        configs = [_make_template_config("c1", 0, min_dur=3.0, max_dur=5.0)]
+        result = create_clips_from_configs("p1", configs)
+        assert isinstance(result[0], EditPlanClip)