diff --git a/start.php b/start.php
index 86ef2534..b2a5a311 100644
--- a/start.php
+++ b/start.php
@@ -30,9 +30,6 @@ if (!defined('APP_DEBUG')) {
     define('APP_DEBUG', $debug);
 }
 
-// 注册自动加载
-Loader::register();
-
 // 加载模式定义文件
 $mode = require MODE_PATH . APP_MODE . EXT;
 
@@ -41,6 +38,9 @@ if (isset($mode['namespace'])) {
     Loader::addNamespace($mode['namespace']);
 }
 
+// 注册自动加载
+Loader::register();
+
 // 加载模式别名定义
 if (isset($mode['alias'])) {
     Loader::addMap($mode['alias']);
diff --git a/tests/thinkphp/library/think/configTest.php b/tests/thinkphp/library/think/configTest.php
index 959a8f3e..f0048a44 100644
--- a/tests/thinkphp/library/think/configTest.php
+++ b/tests/thinkphp/library/think/configTest.php
@@ -94,10 +94,9 @@ class configTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals([], Config::get(null, $range));
         $this->assertEquals(null, Config::get(null, 'does_not_exist'));
         // test $_ENV configuration
-        defined('ENV_PREFIX') or define('ENV_PREFIX', '_TEST_');
-        $name                     = 'test_name';
-        $value                    = 'value';
-        $_ENV[ENV_PREFIX . $name] = $value;
+        $name  = 'test_name';
+        $value = 'value';
+        putenv(ENV_PREFIX . $name . '=' . $value);
         $this->assertEquals($value, Config::get($name, $range));
         // test getting configuration
         $reflectedPropertyConfig->setValue([$range => ['abcd' => 'efg']]);