diff --git a/models/message.js b/models/message.js
index 766e39c..a842bab 100644
--- a/models/message.js
+++ b/models/message.js
@@ -1,7 +1,7 @@
 var mongoose = require('mongoose');
 var Schema = mongoose.Schema;
 var ObjectId = Schema.ObjectId;
-  
+
 /*
  * type:
  * reply: xx 回复了你的话题
@@ -9,10 +9,10 @@ var ObjectId = Schema.ObjectId;
  * follow: xx 关注了你
  * at: xx ＠了你
  */
- 
+
 var MessageSchema = new Schema({
   type: { type: String },
-  master_id: { type: ObjectId, index: true },
+  master_id: { type: ObjectId},
   author_id: { type: ObjectId },
   topic_id: { type: ObjectId },
   reply_id: { type: ObjectId },
@@ -20,4 +20,6 @@ var MessageSchema = new Schema({
   create_at: { type: Date, default: Date.now }
 });
 
+MessageSchema.index({master_id: 1, create_at: -1});
+
 mongoose.model('Message', MessageSchema);