diff --git a/apps/pm/views.py b/apps/pm/views.py
index a4060f86..ecde7008 100644
--- a/apps/pm/views.py
+++ b/apps/pm/views.py
@@ -223,7 +223,12 @@ class MtaskViewSet(CustomModelViewSet):
             raise ParseError('任务数量与分配数量不匹配')
         for v in vdata:
             Mtaskb.objects.get_or_create(mtask=mtask, handle_user=v['handle_user'], count=v['count'])
-        Mtaskb.objects.filter(mtask=mtask).exclude(handle_user__in=userIds).delete()
+        dobjs = Mtaskb.objects.filter(mtask=mtask).exclude(handle_user__in=userIds)
+        from apps.wpm.models import Mlog
+        if Mlog.objects.filter(mtaskb__in=dobjs).exists():
+            raise ParseError('已存在工作日志，无法修改分配')
+        else:
+            dobjs.delete()
         return Response()
 
 class MtaskbViewSet(CustomModelViewSet):