diff --git a/backend/app/services/product_service.py b/backend/app/services/product_service.py
index 59da0df..48ee7e8 100644
--- a/backend/app/services/product_service.py
+++ b/backend/app/services/product_service.py
@@ -2,7 +2,7 @@
 from __future__ import annotations
 import uuid
 from fastapi import HTTPException, status
-from sqlalchemy import select, or_, cast, String
+from sqlalchemy import select, or_, cast, String, delete, update
 from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy.orm import selectinload
 
@@ -503,20 +503,32 @@ async def delete_product(db: AsyncSession, product_id: uuid.UUID) -> None:
     """删除产品及其关联任务"""
     product = await get_product(db, product_id)
 
-    # 删除关联任务记录
     from app.models.task import TaskRecord
+    from app.models.task_log import TaskLog
+
+    # 🚀 1. 切断产品自引用：子产品的 parent_product_id 置空
+    await db.execute(
+        update(Product).where(Product.parent_product_id == product_id).values(parent_product_id=None)
+    )
+
+    # 2. 查询所有关联任务
     tasks_result = await db.execute(
         select(Task).where(Task.product_id == product_id)
     )
     tasks = tasks_result.scalars().all()
+
+    # 🚀 3. 切断任务自引用：子任务的 parent_task_id 置空
     for task in tasks:
         await db.execute(
-            select(TaskRecord).where(TaskRecord.task_id == task.id)
+            update(Task).where(Task.parent_task_id == task.id).values(parent_task_id=None)
         )
-        # 级联删除已在模型中定义，直接删任务
-    # 删除产品（task 有外键 CASCADE？检查模型）
-    # 手动删关联任务确保完整
+
+    # 4. 删除任务记录、日志、任务本身
     for task in tasks:
+        await db.execute(delete(TaskRecord).where(TaskRecord.task_id == task.id))
+        await db.execute(delete(TaskLog).where(TaskLog.task_id == task.id))
         await db.delete(task)
+
+    # 5. 删除产品（product_messages 有 ON DELETE CASCADE 自动级联）
     await db.delete(product)
     await db.commit()