diff --git a/library/think/Route.php b/library/think/Route.php
index eee061f9..4a4aa930 100644
--- a/library/think/Route.php
+++ b/library/think/Route.php
@@ -1093,7 +1093,7 @@ class Route
                 foreach ($matches[1] as $name) {
                     if (strpos($name, '?')) {
                         $name      = substr($name, 0, -1);
-                        $replace[] = '((' . (isset($pattern[$name]) ? $pattern[$name] : '') . ')?)';
+                        $replace[] = '(' . (isset($pattern[$name]) ? $pattern[$name] : '') . '?)';
                     } else {
                         $replace[] = '(' . (isset($pattern[$name]) ? $pattern[$name] : '') . ')';
                     }