diff --git a/backend/app/api/projects.py b/backend/app/api/projects.py
index 858c3bf..306b44f 100644
--- a/backend/app/api/projects.py
+++ b/backend/app/api/projects.py
@@ -123,6 +123,24 @@ async def create_project(
             related_project_id=project.id,
         )
 
+    # 给被分配的代理商发送新项目通知
+    if project.agencies:
+        for agency in project.agencies:
+            agency_user_result = await db.execute(
+                select(User).where(User.id == agency.user_id)
+            )
+            agency_user = agency_user_result.scalar_one_or_none()
+            if agency_user:
+                await create_message(
+                    db=db,
+                    user_id=agency_user.id,
+                    type="new_task",
+                    title="新项目分配",
+                    content=f"品牌方「{brand.name}」将您加入了项目「{project.name}」",
+                    related_project_id=project.id,
+                    sender_name=brand.name,
+                )
+
     return await _project_to_response(project, db)
 
 
@@ -306,6 +324,7 @@ async def assign_agencies(
     if project.brand_id != brand.id:
         raise HTTPException(status_code=403, detail="无权操作此项目")
 
+    newly_assigned = []
     for agency_id in request.agency_ids:
         agency_result = await db.execute(
             select(Agency).where(Agency.id == agency_id)
@@ -313,10 +332,28 @@ async def assign_agencies(
         agency = agency_result.scalar_one_or_none()
         if agency and agency not in project.agencies:
             project.agencies.append(agency)
+            newly_assigned.append(agency)
 
     await db.flush()
     await db.refresh(project)
 
+    # 给新分配的代理商发送通知
+    for agency in newly_assigned:
+        agency_user_result = await db.execute(
+            select(User).where(User.id == agency.user_id)
+        )
+        agency_user = agency_user_result.scalar_one_or_none()
+        if agency_user:
+            await create_message(
+                db=db,
+                user_id=agency_user.id,
+                type="new_task",
+                title="新项目分配",
+                content=f"品牌方「{brand.name}」将您加入了项目「{project.name}」",
+                related_project_id=project.id,
+                sender_name=brand.name,
+            )
+
     return await _project_to_response(project, db)