diff --git a/apps/pm/views.py b/apps/pm/views.py
index 74f72e72..2ca45329 100644
--- a/apps/pm/views.py
+++ b/apps/pm/views.py
@@ -211,6 +211,8 @@ class MtaskViewSet(CustomModelViewSet):
     @transaction.atomic
     def add_mtaskb(self, request, *args, **kwargs):
         mtask = self.get_object()
+        if mtask.state != Mtask.MTASK_ASSGINED:
+            raise ParseError('该任务不可分配')
         sr = MtaskbAddSerializer(data=request.data, many=True)
         sr.is_valid(raise_exception=True)
         vdata = sr.validated_data