diff --git a/pkg/scheduler/plugins/extender/extender.go b/pkg/scheduler/plugins/extender/extender.go
index 21fd1abbe4e..23337a5d261 100644
--- a/pkg/scheduler/plugins/extender/extender.go
+++ b/pkg/scheduler/plugins/extender/extender.go
@@ -176,6 +176,11 @@ func (ep *extenderPlugin) OnSessionOpen(ssn *framework.Session) {
 			if len(resp.ErrorMessage) == 0 {
 				return nil
 			}
+			// keep compatibility with old behavior: error messages length is not zero
+			// but didn't return a code, and code will be 0 for default. Change code to zero for corresponding
+			if resp.Code == api.Success {
+				resp.Code = api.Error
+			}
 			return api.NewFitErrWithStatus(task, node, &api.Status{Code: resp.Code, Reason: resp.ErrorMessage, Plugin: PluginName})
 		})
 	}