diff --git a/backend/plugins/domain/user/handlers.go b/backend/plugins/domain/user/handlers.go
index e3ec20a6..7a602d66 100644
--- a/backend/plugins/domain/user/handlers.go
+++ b/backend/plugins/domain/user/handlers.go
@@ -5,6 +5,7 @@ package user
 
 import (
 	"Wavelet/core/contracts"
+	"Wavelet/pkg/idgen"
 	"Wavelet/pkg/logger"
 	"Wavelet/pkg/response"
 	"context"
@@ -107,6 +108,13 @@ func Login(c *gin.Context) {
 		return
 	}
 
+	if user.ID == 0 {
+		newID := idgen.NextUint64ID()
+		if err := getDB(c.Request.Context()).Model(&User{}).Where("username = ?", user.Username).Update("id", newID).Error; err == nil {
+			user.ID = newID
+		}
+	}
+
 	sess := sessions.Default(c)
 	sess.Set(contracts.AuthUserIDKey, strconv.FormatUint(user.ID, 10))
 	sess.Set(contracts.AuthUserNameKey, user.Username)