diff --git a/HISTORY b/HISTORY
index f6037c1..7d4a4aa 100644
--- a/HISTORY
+++ b/HISTORY
@@ -1,9 +1,10 @@
 
-Version 5.02  2014-07-04
+Version 5.02  2014-07-18
  * corect README spell mistake
  * bug fixed: can't deal sync truncate file exception
  * remove tracker_global.c extern keyword to tracker_global.h
  * change log level from ERROR to DEBUG when IOEVENT_ERROR
+ * php callback should use INIT_ZVAL to init zval variable
 
 Version 5.01  2014-02-02
  * trunk binlog be compressed when trunk init
diff --git a/php_client/fastdfs_client.c b/php_client/fastdfs_client.c
index d884614..e2b35b6 100644
--- a/php_client/fastdfs_client.c
+++ b/php_client/fastdfs_client.c
@@ -2858,12 +2858,16 @@ static int php_fdfs_upload_callback(void *arg, const int64_t file_size, int sock
 	int result;
 	TSRMLS_FETCH();
 
+    INIT_ZVAL(ret);
 	ZVAL_NULL(&ret);
+
+    INIT_ZVAL(zsock);
 	ZVAL_LONG(&zsock, sock);
 
 	pUploadCallback = (php_fdfs_upload_callback_t *)arg;
 	if (pUploadCallback->callback.args == NULL)
 	{
+        INIT_ZVAL(null_args);
 		ZVAL_NULL(&null_args);
 		pUploadCallback->callback.args = &null_args;
 	}
@@ -2907,13 +2911,19 @@ static int php_fdfs_download_callback(void *arg, const int64_t file_size, \
 	int result;
 	TSRMLS_FETCH();
 
+    INIT_ZVAL(ret);
 	ZVAL_NULL(&ret);
+
+    INIT_ZVAL(zfilesize);
 	ZVAL_LONG(&zfilesize, file_size);
+
+    INIT_ZVAL(zdata);
 	ZVAL_STRINGL(&zdata, (char *)data, current_size, 0);
 
 	pCallback = (php_fdfs_callback_t *)arg;
 	if (pCallback->args == NULL)
 	{
+        INIT_ZVAL(null_args);
 		ZVAL_NULL(&null_args);
 		pCallback->args = &null_args;
 	}