diff --git a/Aliyun/Log/Client.php b/Aliyun/Log/Client.php
index bb816cb..2197683 100644
--- a/Aliyun/Log/Client.php
+++ b/Aliyun/Log/Client.php
@@ -10,10 +10,10 @@
 require_once realpath ( dirname ( __FILE__ ) . '/sls.proto.php' );
 require_once realpath ( dirname ( __FILE__ ) . '/protocolbuffers.inc.php' );
 
-if(!defined('API_VERSION'))
-    define('API_VERSION', '0.6.0');
-if(!defined('USER_AGENT'))
-    define('USER_AGENT', 'log-php-sdk-v-0.6.0');
+if(!defined('SLS_API_VERSION'))
+    define('SLS_API_VERSION', '0.6.0');
+if(!defined('SLS_USER_AGENT'))
+    define('SLS_USER_AGENT', 'log-php-sdk-v-0.6.0');
 
 /**
  * Aliyun_Log_Client class is the main class in the SDK. It can be used to
@@ -153,7 +153,7 @@ protected function getHttpResponse($method, $url, $body, $headers) {
         foreach ( $headers as $key => $value )
             $request->add_header ( $key, $value );
         $request->set_method ( $method );
-        $request->set_useragent(USER_AGENT);
+        $request->set_useragent(SLS_USER_AGENT);
         if ($method == "POST" || $method == "PUT")
             $request->set_body ( $body );
         $request->send_request ();
@@ -225,7 +225,7 @@ private function send($method, $project, $body, $resource, $params, $headers) {
             $headers ['Content-Type'] = ''; // If not set, http request will add automatically.
         }
         
-        $headers ['x-log-apiversion'] = API_VERSION;
+        $headers ['x-log-apiversion'] = SLS_API_VERSION;
         $headers ['x-log-signaturemethod'] = 'hmac-sha1';
         if(strlen($credentials->getSecurityToken()) >0)
             $headers ['x-acs-security-token'] = $credentials->getSecurityToken();
diff --git a/docs/namespaces/default.html b/docs/namespaces/default.html
index b2f0e05..878ac4d 100644
--- a/docs/namespaces/default.html
+++ b/docs/namespaces/default.html
@@ -135,21 +135,21 @@
         
                     <div class="namespace-indent">
                 <h3><i class="icon-custom icon-constant"></i> Constants</h3>
-                                        <div id="constant_API_VERSION" class="element ajax clickable constant" data-toggle="collapse" data-target="#constant_API_VERSION .collapse">
-        <h1>API_VERSION<a href="../namespaces/default.html#constant_API_VERSION">¶</a></h1>
+                                        <div id="constant_SLS_API_VERSION" class="element ajax clickable constant" data-toggle="collapse" data-target="#constant_SLS_API_VERSION .collapse">
+        <h1>SLS_API_VERSION<a href="../namespaces/default.html#constant_SLS_API_VERSION">¶</a></h1>
         <p class="short_description"></p>
         <div class="details collapse">
                             
                     </div>
-        <a href="../namespaces/default.html#constant_API_VERSION" class="more">« More »</a>    </div>
+        <a href="../namespaces/default.html#constant_SLS_API_VERSION" class="more">« More »</a>    </div>
 
-                                        <div id="constant_USER_AGENT" class="element ajax clickable constant" data-toggle="collapse" data-target="#constant_USER_AGENT .collapse">
-        <h1>USER_AGENT<a href="../namespaces/default.html#constant_USER_AGENT">¶</a></h1>
+                                        <div id="constant_SLS_USER_AGENT" class="element ajax clickable constant" data-toggle="collapse" data-target="#constant_SLS_USER_AGENT .collapse">
+        <h1>SLS_USER_AGENT<a href="../namespaces/default.html#constant_SLS_USER_AGENT">¶</a></h1>
         <p class="short_description"></p>
         <div class="details collapse">
                             
                     </div>
-        <a href="../namespaces/default.html#constant_USER_AGENT" class="more">« More »</a>    </div>
+        <a href="../namespaces/default.html#constant_SLS_USER_AGENT" class="more">« More »</a>    </div>
 
                             </div>
         
diff --git a/docs/packages/LOG.PHP.SDK.html b/docs/packages/LOG.PHP.SDK.html
index f51a764..ecbdbd2 100644
--- a/docs/packages/LOG.PHP.SDK.html
+++ b/docs/packages/LOG.PHP.SDK.html
@@ -135,18 +135,18 @@
         
                     <div class="package-indent">
                 <h3><i class="icon-custom icon-constant"></i> Constants</h3>
-                                        <div id="API_VERSION" class="element ajax clickable constant">
-        <h1>API_VERSION<a href="../namespaces/default.html#constant_API_VERSION">¶</a></h1>
+                                        <div id="SLS_API_VERSION" class="element ajax clickable constant">
+        <h1>SLS_API_VERSION<a href="../namespaces/default.html#constant_SLS_API_VERSION">¶</a></h1>
         <p class="short_description"></p>
         <div class="details collapse"></div>
-        <a href="../namespaces/default.html#constant_API_VERSION" class="more">« More »</a>
+        <a href="../namespaces/default.html#constant_SLS_API_VERSION" class="more">« More »</a>
     </div>
 
-                                        <div id="USER_AGENT" class="element ajax clickable constant">
-        <h1>USER_AGENT<a href="../namespaces/default.html#constant_USER_AGENT">¶</a></h1>
+                                        <div id="SLS_USER_AGENT" class="element ajax clickable constant">
+        <h1>SLS_USER_AGENT<a href="../namespaces/default.html#constant_SLS_USER_AGENT">¶</a></h1>
         <p class="short_description"></p>
         <div class="details collapse"></div>
-        <a href="../namespaces/default.html#constant_USER_AGENT" class="more">« More »</a>
+        <a href="../namespaces/default.html#constant_SLS_USER_AGENT" class="more">« More »</a>
     </div>
 
                             </div>
diff --git a/docs/packages/SLS_PHP_SDK.html b/docs/packages/SLS_PHP_SDK.html
index 366a80d..267f0cb 100644
--- a/docs/packages/SLS_PHP_SDK.html
+++ b/docs/packages/SLS_PHP_SDK.html
@@ -96,8 +96,8 @@
 <li><a href="#Aliyun_Log_Models_GetLogsResponse" title="The response of the GetLog API from sls.">Aliyun_Log_Models_GetLogsResponse</a></li>
 <li class="nav-header">
 <i title="Constants" class="icon-custom icon-constant"></i> Constants</li>
-<li class="constant  "><a href="#constant_API_VERSION" title="API_VERSION() :: "><span class="description">API_VERSION</span><pre>API_VERSION</pre></a></li>
-<li class="constant  "><a href="#constant_USER_AGENT" title="USER_AGENT() :: "><span class="description">USER_AGENT</span><pre>USER_AGENT</pre></a></li>
+<li class="constant  "><a href="#constant_SLS_API_VERSION" title="SLS_API_VERSION() :: "><span class="description">SLS_API_VERSION</span><pre>SLS_API_VERSION</pre></a></li>
+<li class="constant  "><a href="#constant_SLS_USER_AGENT" title="SLS_USER_AGENT() :: "><span class="description">SLS_USER_AGENT</span><pre>SLS_USER_AGENT</pre></a></li>
 </ul>
 </div>
 <div class="span8 package-contents">
@@ -305,9 +305,9 @@ <h1>ResponseCore<a href="../classes/ResponseCore.html">¶</a>
 </div>
 <h3>
 <i title="Constants" class="icon-custom icon-constant"></i> Constants</h3>
-<a xmlns:php="http://php.net/xsl" id="constant_API_VERSION"> </a><div xmlns:php="http://php.net/xsl" class="element clickable constant  constant_API_VERSION" data-toggle="collapse" data-target=".constant_API_VERSION .collapse" title="">
-<h2>API_VERSION</h2>
-<pre>API_VERSION = '0.4.0' </pre>
+<a xmlns:php="http://php.net/xsl" id="constant_SLS_API_VERSION"> </a><div xmlns:php="http://php.net/xsl" class="element clickable constant  constant_SLS_API_VERSION" data-toggle="collapse" data-target=".constant_SLS_API_VERSION .collapse" title="">
+<h2>SLS_API_VERSION</h2>
+<pre>SLS_API_VERSION = '0.4.0' </pre>
 <div class="labels"></div>
 <div class="row collapse"><div class="detail-description">
 <div class="long_description"></div>
@@ -317,9 +317,9 @@ <h2>API_VERSION</h2>
 </tr></table>
 </div></div>
 </div>
-<a xmlns:php="http://php.net/xsl" id="constant_USER_AGENT"> </a><div xmlns:php="http://php.net/xsl" class="element clickable constant  constant_USER_AGENT" data-toggle="collapse" data-target=".constant_USER_AGENT .collapse" title="">
-<h2>USER_AGENT</h2>
-<pre>USER_AGENT = 'sls-php-sdk-v-0.4.1' </pre>
+<a xmlns:php="http://php.net/xsl" id="constant_SLS_USER_AGENT"> </a><div xmlns:php="http://php.net/xsl" class="element clickable constant  constant_SLS_USER_AGENT" data-toggle="collapse" data-target=".constant_SLS_USER_AGENT .collapse" title="">
+<h2>SLS_USER_AGENT</h2>
+<pre>SLS_USER_AGENT = 'sls-php-sdk-v-0.4.1' </pre>
 <div class="labels"></div>
 <div class="row collapse"><div class="detail-description">
 <div class="long_description"></div>
diff --git a/docs/packages/default.html b/docs/packages/default.html
index 6048e4d..b2b6925 100644
--- a/docs/packages/default.html
+++ b/docs/packages/default.html
@@ -156,18 +156,18 @@
         
                     <div class="package-indent">
                 <h3><i class="icon-custom icon-constant"></i> Constants</h3>
-                                        <div id="API_VERSION" class="element ajax clickable constant">
-        <h1>API_VERSION<a href="../namespaces/default.html#constant_API_VERSION">¶</a></h1>
+                                        <div id="SLS_API_VERSION" class="element ajax clickable constant">
+        <h1>SLS_API_VERSION<a href="../namespaces/default.html#constant_SLS_API_VERSION">¶</a></h1>
         <p class="short_description"></p>
         <div class="details collapse"></div>
-        <a href="../namespaces/default.html#constant_API_VERSION" class="more">« More »</a>
+        <a href="../namespaces/default.html#constant_SLS_API_VERSION" class="more">« More »</a>
     </div>
 
-                                        <div id="USER_AGENT" class="element ajax clickable constant">
-        <h1>USER_AGENT<a href="../namespaces/default.html#constant_USER_AGENT">¶</a></h1>
+                                        <div id="SLS_USER_AGENT" class="element ajax clickable constant">
+        <h1>SLS_USER_AGENT<a href="../namespaces/default.html#constant_SLS_USER_AGENT">¶</a></h1>
         <p class="short_description"></p>
         <div class="details collapse"></div>
-        <a href="../namespaces/default.html#constant_USER_AGENT" class="more">« More »</a>
+        <a href="../namespaces/default.html#constant_SLS_USER_AGENT" class="more">« More »</a>
     </div>
 
                             </div>
diff --git a/docs/structure.xml b/docs/structure.xml
index 54dcf24..69ed6c7 100644
--- a/docs/structure.xml
+++ b/docs/structure.xml
@@ -2991,8 +2991,8 @@ All rights reserved</description>
       <tag name="package" line="0" description="SLS_PHP_SDK"/>
     </docblock>
     <constant namespace="" line="14" package="SLS_PHP_SDK">
-      <name>API_VERSION</name>
-      <full_name>\API_VERSION</full_name>
+      <name>SLS_API_VERSION</name>
+      <full_name>\SLS_API_VERSION</full_name>
       <value>'0.4.0'</value>
       <docblock line="14">
         <description></description>
@@ -3001,8 +3001,8 @@ All rights reserved</description>
       </docblock>
     </constant>
     <constant namespace="" line="16" package="SLS_PHP_SDK">
-      <name>USER_AGENT</name>
-      <full_name>\USER_AGENT</full_name>
+      <name>SLS_USER_AGENT</name>
+      <full_name>\SLS_USER_AGENT</full_name>
       <value>'sls-php-sdk-v-0.4.1'</value>
       <docblock line="16">
         <description></description>