diff --git a/erp/staff_user.go b/erp/staff_user.go
index ab4b405..e9a0cb2 100644
--- a/erp/staff_user.go
+++ b/erp/staff_user.go
@@ -65,7 +65,7 @@ func (e *StaffUser) Login(req *LoginReq) (*LoginRsp, error) {
 
 	var reqBody string
 
-	reqBody = fmt.Sprintf(`{"username":"%s","password":"%s", timestamp":"%s","type":"%s"}`,
+	reqBody = fmt.Sprintf(`{"username":"%s","password":"%s", "timestamp":"%s","type":"%s"}`,
 		req.Username, req.Password, req.Timestamp, req.Type)
 
 	reqUrl := e.GetBaseUrl() + "/ext/staff/user/login"