diff --git a/convention.php b/convention.php
index 00ed0452..62ab0ea4 100644
--- a/convention.php
+++ b/convention.php
@@ -89,8 +89,8 @@ return [
     'url_route_must'         => false,
     // 域名部署
     'url_domain_deploy'      => false,
-    // 当前默认URL根地址
-    'default_url_root'       => '',
+    // 默认Host地址
+    'default_host'           => '',
     // 域名根，如thinkphp.cn
     'url_domain_root'        => '',
     // 是否自动转换URL中的控制器和操作名
diff --git a/library/think/Request.php b/library/think/Request.php
index 2712c742..13089576 100644
--- a/library/think/Request.php
+++ b/library/think/Request.php
@@ -132,9 +132,7 @@ class Request
         if (is_null($this->filter)) {
             $this->filter = Config::get('default_filter');
         }
-        if (Config::get('default_url_root')) {
-            $this->root(Config::get('default_url_root'));
-        }
+
         // 保存 php://input
         $this->input = file_get_contents('php://input');
     }
diff --git a/library/think/Url.php b/library/think/Url.php
index 8e716a5b..24a2b4e3 100644
--- a/library/think/Url.php
+++ b/library/think/Url.php
@@ -235,7 +235,7 @@ class Url
         $rootDomain = Config::get('url_domain_root');
         if (true === $domain) {
             // 自动判断域名
-            $domain = $request->host();
+            $domain = Config::get('default_host') ?: $request->host();
 
             $domains = Route::rules('domain');
             if ($domains) {
@@ -265,7 +265,7 @@ class Url
 
         } else {
             if (empty($rootDomain)) {
-                $host       = $request->host();
+                $host       = Config::get('default_host') ?: $request->host();
                 $rootDomain = substr_count($host, '.') > 1 ? substr(strstr($host, '.'), 1) : $host;
             }
             if (substr_count($domain, '.') < 2 && !strpos($domain, $rootDomain)) {