diff --git a/service/controller/controller.go b/service/controller/controller.go
index 7533e10..e348c6d 100644
--- a/service/controller/controller.go
+++ b/service/controller/controller.go
@@ -346,7 +346,7 @@ func (c *Controller) addNewUser(userInfo *[]api.UserInfo, nodeInfo *api.NodeInfo
 			users = c.buildVlessUser(userInfo)
 		} else {
 			var alterID uint16 = 0
-			if c.panelType == "V2board" {
+			if c.panelType == "V2board" && len(*userInfo) > 0 {
 				// use latest userInfo
 				alterID = (*userInfo)[0].AlterID
 			} else {