diff --git a/api/v1/topic.js b/api/v1/topic.js
index 3efb2ed..ea7bf2c 100644
--- a/api/v1/topic.js
+++ b/api/v1/topic.js
@@ -94,7 +94,7 @@ var show = function (req, res, next) {
       reply =  _.pick(reply, ['id', 'author', 'content', 'ups', 'create_at', 'reply_id']);
       reply.reply_id = reply.reply_id || null;
 
-      if (reply.ups && req.user && reply.ups.indexOf(req.user.id) != -1) {
+      if (reply.ups && req.user && reply.ups.indexOf(req.user._id) != -1) {
         reply.is_uped = true;
       } else {
         reply.is_uped = false;