diff --git a/library/think/loader.php b/library/think/loader.php
index 734fe603..cc0cfa80 100644
--- a/library/think/loader.php
+++ b/library/think/loader.php
@@ -36,23 +36,24 @@ class Loader
             include $file;
         } else {
             // 命名空间自动加载
-            $name = strtolower(strstr($class, '\\', true));
+            $name  = strtolower(strstr($class, '\\', true));
+            $class = substr($class, strlen($name) + 1);
             if (isset(self::$namespace[$name])) {
                 // 注册的命名空间
                 $path = self::$namespace[$name];
             } elseif (in_array($name, ['think', 'behavior', 'traits']) || is_dir(LIB_PATH . $name)) {
                 // 核心类库命名空间
-                $path = LIB_PATH . $name;
+                $path = LIB_PATH . $name . DS;
             } elseif (APP_NAMESPACE == $name) {
                 // 项目命名空间
                 $path = APP_PATH;
             } elseif (is_dir(EXTEND_PATH . $name)) {
                 // 扩展类库命名空间
-                $path = EXTEND_PATH . $name;
+                $path = EXTEND_PATH . $name . DS;
             } else {
                 return;
             }
-            $filename = $path . str_replace('\\', DS, str_replace('\\_', '\\', strtolower(trim(preg_replace("/[A-Z]/", "_\\0", strstr($class, '\\')), "_")))) . EXT;
+            $filename = $path . str_replace('\\', DS, str_replace('\\_', '\\', strtolower(trim(preg_replace("/[A-Z]/", "_\\0", $class), "_")))) . EXT;
             if (is_file($filename)) {
                 include $filename;
             }