diff --git a/apps/api/app/api/routes/templates_editor/clips.py b/apps/api/app/api/routes/templates_editor/clips.py
index b678b9d15..5ee2946fb 100755
--- a/apps/api/app/api/routes/templates_editor/clips.py
+++ b/apps/api/app/api/routes/templates_editor/clips.py
@@ -690,16 +690,16 @@ def _update_mediakit_recommendations_async(  # pragma: no cover
     此函数在后台异步执行，不影响接口响应时间。
     失败时静默处理，不影响已创建的片段。
     """
-    from app.config import settings
-
     from packages.adapters.sqlalchemy_impl.asset_repository import SQLAlchemyAssetRepository
-    from packages.adapters.sqlalchemy_impl.session import build_session_factory
+    from packages.adapters.sqlalchemy_impl.session import SessionLocal
 
     db = None
     try:
-        # 创建独立的数据库 session（不复用请求 session）
-        _, session_factory = build_session_factory(settings.DATABASE_URL)
-        db = session_factory()
+        # 复用应用全局 Session（避免每次创建新连接池导致资源泄漏）
+        if SessionLocal is None:
+            logger.warning("后台任务: SessionLocal 未初始化，跳过 MediaKit 更新")
+            return
+        db = SessionLocal()
 
         # 初始化服务
         asset_repo = SQLAlchemyAssetRepository(db)
@@ -711,14 +711,32 @@ def _update_mediakit_recommendations_async(  # pragma: no cover
             logger.info("后台任务: MediaKit 无推荐结果，跳过更新")
             return
 
-        # 查询该 plan 的所有片段
-        clips = plan_svc.list_clips(plan_id, skip=0, limit=500)
+        # 查询该 plan 的所有片段（分批获取，避免硬编码 limit 截断）
+        batch_size = 500
+        all_clips = []
+        offset = 0
+        while True:
+            batch = plan_svc.list_clips(plan_id, skip=offset, limit=batch_size)
+            if not batch:
+                break
+            all_clips.extend(batch)
+            if len(batch) < batch_size:
+                break
+            offset += batch_size
+        clips = all_clips
+
         if not clips:
             logger.info("后台任务: plan_id=%s 无片段，跳过更新", plan_id)
             return
 
-        # 按 asset_id 分组，跟踪已使用时间段
+        # 按 asset_id 分组，初始化已使用时间段（包含所有片段的当前随机时间）
         used_segments: dict[str, list[tuple[float, float]]] = {}
+        for clip in clips:
+            aid = getattr(clip, "asset_id", "") or ""
+            if aid and clip.start_time is not None:
+                used_segments.setdefault(aid, []).append(
+                    (clip.start_time, clip.start_time + clip.duration)
+                )
 
         # 遍历片段，按 asset_id 匹配推荐时间
         for clip in clips: