diff --git a/src/categories.js b/src/categories.js
index 408eaf8fbb..165f9e2c3f 100644
--- a/src/categories.js
+++ b/src/categories.js
@@ -314,6 +314,32 @@ var	RDB = require('./redis.js'),
 		});
 	}
 
+	Categories.moveRecentReplies = function(tid, oldCid, cid, callback) {
+		topics.getPids(tid, function(err, pids) {
+			if(!err) {
+
+				function movePost(pid, callback) {
+					posts.getPostField(pid, 'timestamp', function(timestamp) {
+						RDB.zrem('categories:recent_posts:cid:' + oldCid, pid);	
+						RDB.zadd('categories:recent_posts:cid:' + cid, timestamp, pid);	
+					});
+				}
+
+				async.each(pids, movePost, function(err) {
+					if(!err) {
+						callback(null, 1)
+					} else {
+						console.log(err);
+						callback(err, null);
+					}
+				});
+			} else {
+				console.log(err);
+				callback(err, null);
+			}
+		});
+	}
+
 	Categories.getCategoryData = function(cid, callback) {
 		RDB.hgetall('category:' + cid, function(err, data) {
 			if(err === null)
diff --git a/src/posts.js b/src/posts.js
index 0feeca6b02..d8b0079a30 100644
--- a/src/posts.js
+++ b/src/posts.js
@@ -218,9 +218,9 @@ marked.setOptions({
 
 			Posts.create(uid, tid, content, images, function(postData) {
 				if (postData) {
-					RDB.rpush('tid:' + tid + ':posts', postData.pid);
+					topics.addPostToTopic(tid, postData.pid);
 
-					RDB.del('tid:' + tid + ':read_by_uid'); 
+					topics.markUnRead(tid);
 
 					Posts.get_cid_by_pid(postData.pid, function(cid) {
 						RDB.del('cid:' + cid + ':read_by_uid', function(err, data) {
diff --git a/src/threadTools.js b/src/threadTools.js
index f3d5ceca42..da0366cc17 100644
--- a/src/threadTools.js
+++ b/src/threadTools.js
@@ -171,6 +171,12 @@ var	RDB = require('./redis.js'),
 
 					topics.setTopicField(tid, 'cid', cid);
 					
+					categories.moveRecentReplies(tid, oldCid, cid, function(err, data) {
+						if(err) {
+							console.log(err);
+						}
+					});
+
 					categories.incrementCategoryFieldBy(oldCid, 'topic_count', -1);
 					categories.incrementCategoryFieldBy(cid, 'topic_count', 1);
 
diff --git a/src/topics.js b/src/topics.js
index b304fc5f20..e0270a1d04 100644
--- a/src/topics.js
+++ b/src/topics.js
@@ -226,6 +226,10 @@ marked.setOptions({
 		});
 	}
 
+	Topics.markUnRead = function(tid) {
+		RDB.del('tid:' + tid + ':read_by_uid'); 
+	}
+
 	Topics.markAsRead = function(tid, uid) {
 		
 		RDB.sadd(schema.topics(tid).read_by_uid, uid);
@@ -455,4 +459,12 @@ marked.setOptions({
 		Topics.setTopicField(tid, 'lastposttime', timestamp);
 	}
 	
+	Topics.addPostToTopic = function(tid, pid) {
+		RDB.rpush('tid:' + tid + ':posts', pid);
+	}
+
+	Topics.getPids = function(tid, callback) {
+		RDB.lrange('tid:' + tid + ':posts', 0, -1, callback);
+	}
+
 }(exports));
\ No newline at end of file