diff --git a/apps/api/app/api/routes/generation_tasks.py b/apps/api/app/api/routes/generation_tasks.py
index f7431ac0a..f13a0121d 100644
--- a/apps/api/app/api/routes/generation_tasks.py
+++ b/apps/api/app/api/routes/generation_tasks.py
@@ -5,6 +5,7 @@ from app.api.routes.permissions import require_workspace_member
 from app.core.celery_app import celery_app
 from app.dependencies import (
     get_asset_library_repository,
+    get_asset_repository,
     get_generated_video_repository,
     get_generation_task_repository,
     get_project_repository,
@@ -63,6 +64,18 @@ def _to_generated_video_response(item) -> GeneratedVideoResponse:
     )
 
 
+def _ensure_library_has_ready_video_assets(assets) -> None:
+    ready_video_assets = [
+        asset for asset in assets
+        if asset.status.value == "ready" and asset.mime_type.startswith("video")
+    ]
+    if not ready_video_assets:
+        raise HTTPException(
+            status_code=422,
+            detail="当前素材库没有 ready 状态的视频素材，请先上传并等待导入完成后再生成。",
+        )
+
+
 @router.post("/tasks", response_model=GenerationTaskResponse)
 def create_generation_task(
     request: CreateGenerationTaskRequest,
@@ -70,6 +83,7 @@ def create_generation_task(
     generation_task_repository: Any = Depends(get_generation_task_repository),
     project_repository: Any = Depends(get_project_repository),
     asset_library_repository: Any = Depends(get_asset_library_repository),
+    asset_repository: Any = Depends(get_asset_repository),
     workspace_member_repository: WorkspaceMemberRepository = Depends(get_workspace_member_repository),
 ) -> GenerationTaskResponse:
     require_workspace_member(request.workspace_id, authenticated_user, workspace_member_repository)
@@ -79,6 +93,8 @@ def create_generation_task(
     library = asset_library_repository.get(request.asset_library_id)
     if library is None or library.workspace_id != request.workspace_id or library.project_id != request.project_id:
         raise HTTPException(status_code=404, detail=f"AssetLibrary {request.asset_library_id} not found")
+    assets = asset_repository.list_by_library(request.asset_library_id)
+    _ensure_library_has_ready_video_assets(assets)
 
     use_case = CreateGenerationTaskUseCase(generation_task_repository)
     task = use_case.execute(
diff --git a/tests/unit/test_generation_preflight.py b/tests/unit/test_generation_preflight.py
new file mode 100644
index 000000000..955d65da3
--- /dev/null
+++ b/tests/unit/test_generation_preflight.py
@@ -0,0 +1,40 @@
+import sys
+from pathlib import Path
+
+import pytest
+from fastapi import HTTPException
+
+sys.path.insert(0, str(Path(__file__).resolve().parents[2] / "apps" / "api"))
+
+from app.api.routes.generation_tasks import _ensure_library_has_ready_video_assets
+from packages.domain import Asset, AssetStatus
+
+
+def _asset(name: str, mime_type: str, status: AssetStatus) -> Asset:
+    return Asset.create(
+        workspace_id="workspace-1",
+        project_id="project-1",
+        library_id="library-1",
+        name=name,
+        storage_key=f"uploads/{name}",
+        mime_type=mime_type,
+        file_size=1024,
+        status=status,
+    )
+
+
+def test_generation_preflight_rejects_library_without_ready_video():
+    with pytest.raises(HTTPException) as exc_info:
+        _ensure_library_has_ready_video_assets([
+            _asset("image.jpg", "image/jpeg", AssetStatus.READY),
+            _asset("video.mp4", "video/mp4", AssetStatus.UPLOADING),
+        ])
+
+    assert exc_info.value.status_code == 422
+    assert "ready 状态的视频素材" in exc_info.value.detail
+
+
+def test_generation_preflight_accepts_ready_video():
+    _ensure_library_has_ready_video_assets([
+        _asset("video.mp4", "video/mp4", AssetStatus.READY),
+    ])