diff --git a/library/think/Session.php b/library/think/Session.php
index 1b419763..ee43bb77 100644
--- a/library/think/Session.php
+++ b/library/think/Session.php
@@ -17,6 +17,7 @@ use think\exception\ClassNotFoundException;
 class Session
 {
     protected static $prefix = '';
+    protected static $init   = null;
 
     /**
      * 设置或者获取session作用域（前缀）
@@ -98,6 +99,22 @@ class Session
         }
         if ($isDoStart) {
             session_start();
+            self::$init = true;
+        } else {
+            self::$init = false;
+        }
+    }
+
+    /**
+     * session自动启动或者初始化
+     * @return void
+     */
+    public static function boot()
+    {
+        if (is_null(self::$init)) {
+            self::init();
+        } elseif (false === self::$init) {
+            session_start();
         }
     }
 
@@ -110,7 +127,8 @@ class Session
      */
     public static function set($name, $value = '', $prefix = null)
     {
-        !isset($_SESSION) && self::init();
+        empty(self::$init) && self::boot();
+
         $prefix = !is_null($prefix) ? $prefix : self::$prefix;
         if (strpos($name, '.')) {
             // 二维数组赋值
@@ -135,7 +153,7 @@ class Session
      */
     public static function get($name = '', $prefix = null)
     {
-        !isset($_SESSION) && self::init();
+        empty(self::$init) && self::boot();
         $prefix = !is_null($prefix) ? $prefix : self::$prefix;
         if ('' == $name) {
             // 获取全部的session
@@ -167,7 +185,7 @@ class Session
      */
     public static function delete($name, $prefix = null)
     {
-        !isset($_SESSION) && self::init();
+        empty(self::$init) && self::boot();
         $prefix = !is_null($prefix) ? $prefix : self::$prefix;
         if (strpos($name, '.')) {
             list($name1, $name2) = explode('.', $name);
@@ -192,7 +210,7 @@ class Session
      */
     public static function clear($prefix = null)
     {
-        !isset($_SESSION) && self::init();
+        empty(self::$init) && self::boot();
         $prefix = !is_null($prefix) ? $prefix : self::$prefix;
         if ($prefix) {
             unset($_SESSION[$prefix]);
@@ -209,7 +227,7 @@ class Session
      */
     public static function has($name, $prefix = null)
     {
-        !isset($_SESSION) && self::init();
+        empty(self::$init) && self::boot();
         $prefix = !is_null($prefix) ? $prefix : self::$prefix;
         if (strpos($name, '.')) {
             // 支持数组
@@ -240,6 +258,7 @@ class Session
         }
         session_unset();
         session_destroy();
+        self::$init = null;
     }
 
     /**
@@ -260,5 +279,6 @@ class Session
     {
         // 暂停session
         session_write_close();
+        self::$init = false;
     }
 }