diff --git a/README.md b/README.md
index 496cbb58c4..2c489236e7 100755
--- a/README.md
+++ b/README.md
@@ -207,6 +207,7 @@ Please select your language:
 
 ### V2 changes
 
+* v2.0, 2017-01-22, for [#752][bug #752] release the io then free it for kbps. 2.0.232
 * v2.0, 2017-01-18, fix [#750][bug #750] use specific error code for dns resolve. 2.0.231
 * <strong>v2.0, 2017-01-18, [2.0 beta4(2.0.230)][r2.0b4] released. 86334 lines.</strong>
 * v2.0, 2017-01-18, fix [#749][bug #749], timestamp overflow for ATC. 2.0.230
@@ -1370,6 +1371,7 @@ Winlin
 [bug #740]: https://github.com/ossrs/srs/issues/740
 [bug #749]: https://github.com/ossrs/srs/issues/749
 [bug #750]: https://github.com/ossrs/srs/issues/750
+[bug #752]: https://github.com/ossrs/srs/issues/752
 [bug #xxxxxxxxxx]: https://github.com/ossrs/srs/issues/xxxxxxxxxx
 
 [bug #735]: https://github.com/ossrs/srs/issues/735
diff --git a/trunk/src/app/srs_app_edge.cpp b/trunk/src/app/srs_app_edge.cpp
index f9baa59137..8de0c05e22 100644
--- a/trunk/src/app/srs_app_edge.cpp
+++ b/trunk/src/app/srs_app_edge.cpp
@@ -483,7 +483,6 @@ void SrsEdgeForwarder::stop()
 {
     pthread->stop();
     queue->clear();
-    
     srs_freep(sdk);
 }
 
diff --git a/trunk/src/app/srs_app_rtmp_conn.cpp b/trunk/src/app/srs_app_rtmp_conn.cpp
index 7a056d2dbd..19005075bf 100644
--- a/trunk/src/app/srs_app_rtmp_conn.cpp
+++ b/trunk/src/app/srs_app_rtmp_conn.cpp
@@ -138,9 +138,9 @@ int SrsSimpleRtmpClient::connect()
 
 void SrsSimpleRtmpClient::close()
 {
+    kbps->set_io(NULL, NULL);
     srs_freep(client);
     srs_freep(transport);
-    kbps->set_io(NULL, NULL);
 }
 
 int SrsSimpleRtmpClient::connect_app()
diff --git a/trunk/src/protocol/srs_protocol_kbps.hpp b/trunk/src/protocol/srs_protocol_kbps.hpp
index ff6f0cec02..7e7d9012a8 100644
--- a/trunk/src/protocol/srs_protocol_kbps.hpp
+++ b/trunk/src/protocol/srs_protocol_kbps.hpp
@@ -161,7 +161,7 @@ class IKbpsDelta
  *      SrsKbps* kbps = ...;
  *      kbps->set_io(in, out);
  *      // both kbps->get_recv_bytes() and kbps->get_send_bytes() are available.
-*       // we can use the kbps as the data source of another kbps:
+ *       // we can use the kbps as the data source of another kbps:
  *      SrsKbps* user = ...;
  *      user->set_io(kbps, kbps);
  *   the server never know how many bytes already send/recv, for the connection maybe closed.
@@ -176,14 +176,15 @@ class SrsKbps : public virtual ISrsProtocolStatistic, public virtual IKbpsDelta
     virtual ~SrsKbps();
 public:
     /**
-    * set io to start new session.
-    * set the underlayer reader/writer,
-    * if the io destroied, for instance, the forwarder reconnect,
-    * user must set the io of SrsKbps to NULL to continue to use the kbps object.
-    * @param in the input stream statistic. can be NULL.
-    * @param out the output stream statistic. can be NULL.
-    * @remark if in/out is NULL, use the cached data for kbps.
-    */
+     * set io to start new session.
+     * set the underlayer reader/writer,
+     * if the io destroied, for instance, the forwarder reconnect,
+     * user must set the io of SrsKbps to NULL to continue to use the kbps object.
+     * @param in the input stream statistic. can be NULL.
+     * @param out the output stream statistic. can be NULL.
+     * @remark if in/out is NULL, use the cached data for kbps.
+     * @remark User must set_io(NULL, NULL) then free the in and out.
+     */
     virtual void set_io(ISrsProtocolStatistic* in, ISrsProtocolStatistic* out);
 public:
     /**