diff --git a/seahub/api2/endpoints/copy_move_task.py b/seahub/api2/endpoints/copy_move_task.py
index ae417b1145..e5e55dcfe0 100644
--- a/seahub/api2/endpoints/copy_move_task.py
+++ b/seahub/api2/endpoints/copy_move_task.py
@@ -121,10 +121,10 @@ class CopyMoveTaskView(APIView):
         username = request.user.username
         if operation == 'move':
             if dirent_type == 'dir' and src_repo_id == dst_repo_id and \
-                    dst_parent_dir.startswith(src_parent_dir + '/'):
+                    dst_parent_dir.startswith(src_dirent_path + '/'):
 
                 error_msg = _(u'Can not move directory %(src)s to its subdirectory %(des)s') \
-                    % {'src': escape(src_parent_dir), 'des': escape( dst_parent_dir)}
+                    % {'src': escape(src_dirent_path), 'des': escape(dst_parent_dir)}
                 return api_error(status.HTTP_400_BAD_REQUEST, error_msg)
 
             # permission check for src parent dir