diff --git a/README.md b/README.md
index b809f33..af7b1ed 100644
--- a/README.md
+++ b/README.md
@@ -20,7 +20,7 @@ PHP支付SDK（微信支付 + 支付宝支付）
 ## 声明
 - 代码与框架部分参考于互联网开源项目
 - `SDK`全部源码基于`MIT`协议开源，完全免费
-- **开发交流`QQ`群：513350915（新）**
+- **开发交流`QQ`群：513350915**
 
 若对您有帮助，可以**赞助**支持下作者哦！
 ----
diff --git a/src/Contracts/HttpService.php b/src/Contracts/HttpService.php
index 853ae35..88657b5 100644
--- a/src/Contracts/HttpService.php
+++ b/src/Contracts/HttpService.php
@@ -20,6 +20,12 @@
 class HttpService
 {
 
+    /**
+     * 缓存路径
+     * @var null
+     */
+    public static $cachePath = null;
+
     /**
      * 以get访问模拟访问
      * @param string $url 访问URL
@@ -109,4 +115,48 @@ private static function build($data)
         }
         return $data;
     }
+
+    /**
+     * 缓存配置与存储
+     * @param string $name 缓存名称
+     * @param string $value 缓存内容
+     * @param int $expired 缓存时间(0表示永久缓存)
+     * @return bool
+     */
+    public static function setCache($name, $value = '', $expired = 3600)
+    {
+        $cachepath = empty(self::$cachePath) ? self::$cachePath : dirname(__DIR__) . '/Cache/';
+        file_exists($cachepath) || mkdir($cachepath, 0755, true);
+        $cachestri = serialize(['name' => $name, 'value' => $value, 'expired' => time() + intval($expired)]);
+        return file_put_contents($cachepath . md5($name), $cachestri);
+    }
+
+    /**
+     * 获取缓存内容
+     * @param string $name 缓存名称
+     * @return null|mixed
+     */
+    public static function getCache($name)
+    {
+        $cachefile = (empty(self::$cachePath) ? self::$cachePath : dirname(__DIR__) . '/Cache/') . md5($name);
+        if (file_exists($cachefile) && ($content = file_get_contents($cachefile))) {
+            $data = unserialize($content);
+            if (isset($data['expired']) && (intval($data['expired']) === 0 || intval($data['expired']) >= time())) {
+                return $data['value'];
+            }
+            self::delCache($name);
+        }
+        return null;
+    }
+
+    /**
+     * 移除缓存文件
+     * @param string $name 缓存名称
+     * @return bool
+     */
+    public static function delCache($name)
+    {
+        $cachefile = (empty(self::$cachePath) ? self::$cachePath : dirname(__DIR__) . '/Cache/') . md5($name);
+        return file_exists($cachefile) ? unlink($cachefile) : true;
+    }
 }
\ No newline at end of file
diff --git a/src/Gateways/Wechat/Wechat.php b/src/Gateways/Wechat/Wechat.php
index 4d2d0f2..93ac140 100644
--- a/src/Gateways/Wechat/Wechat.php
+++ b/src/Gateways/Wechat/Wechat.php
@@ -14,6 +14,7 @@
 
 use Pay\Contracts\Config;
 use Pay\Contracts\GatewayInterface;
+use Pay\Contracts\HttpService;
 use Pay\Exceptions\Exception;
 use Pay\Exceptions\GatewayException;
 use Pay\Exceptions\InvalidArgumentException;
@@ -98,14 +99,19 @@ public function __construct(array $config)
             $this->gateway_micropay = 'https://api.mch.weixin.qq.com/sandboxnew/pay/micropay';
             $this->gateway_bill = 'https://api.mch.weixin.qq.com/sandboxnew/pay/downloadbill';
             // 沙箱验证签名及沙箱密钥更新
-            $data = array('mch_id' => $this->userConfig->get('mch_id', ''), 'nonce_str' => $this->createNonceStr('32'));
-            $data['sign'] = $this->getSign($data);
-            $result = $this->fromXml($this->post('https://api.mch.weixin.qq.com/sandboxnew/pay/getsignkey', $this->toXml($data)));
-            if (isset($result['return_code']) && $result['return_code'] === 'SUCCESS') {
-                $this->userConfig->set('mch_key', $result['sandbox_signkey']);
-            } else {
-                throw new Exception('沙箱验证签名及获取沙箱密钥失败！');
+            $sandbox_signkey = HttpService::getCache('sandbox_signkey');
+            if (empty($sandbox_signkey)) {
+                $data = ['mch_id' => $this->userConfig->get('mch_id', ''), 'nonce_str' => $this->createNonceStr('32')];
+                $data['sign'] = $this->getSign($data);
+                $result = $this->fromXml($this->post('https://api.mch.weixin.qq.com/sandboxnew/pay/getsignkey', $this->toXml($data)));
+                if (isset($result['return_code']) && $result['return_code'] === 'SUCCESS') {
+                    $sandbox_signkey = $result['sandbox_signkey'];
+                    HttpService::setCache('sandbox_signkey', $sandbox_signkey);
+                } else {
+                    throw new Exception('沙箱验证签名及获取沙箱密钥失败！');
+                }
             }
+            $this->userConfig->set('mch_key', $sandbox_signkey);
         }
         $this->config = [
             'appid'      => $this->userConfig->get('app_id', ''),
@@ -121,6 +127,7 @@ public function __construct(array $config)
      * 订单退款操作
      * @param array $options
      * @return array
+     * @throws GatewayException
      */
     public function refund($options = [])
     {
@@ -134,6 +141,7 @@ public function refund($options = [])
      * 关闭正在进行的订单
      * @param string $out_trade_no
      * @return array
+     * @throws GatewayException
      */
     public function close($out_trade_no = '')
     {
@@ -146,6 +154,7 @@ public function close($out_trade_no = '')
      * 查询订单状态
      * @param string $out_trade_no
      * @return array
+     * @throws GatewayException
      */
     public function find($out_trade_no = '')
     {
@@ -176,6 +185,7 @@ abstract protected function getTradeType();
     /**
      * @param array $options
      * @return array
+     * @throws GatewayException
      */
     protected function preOrder($options = [])
     {