diff --git a/base.php b/base.php
index 66d53e9f..80a6e28f 100644
--- a/base.php
+++ b/base.php
@@ -10,7 +10,7 @@
 // +----------------------------------------------------------------------
 
 define('THINK_VERSION', '5.0.0 RC4');
-define('THINK_START_TIME', number_format(microtime(true), 8, '.', ''));
+define('THINK_START_TIME', microtime(true));
 define('THINK_START_MEM', memory_get_usage());
 define('EXT', '.php');
 define('DS', DIRECTORY_SEPARATOR);
diff --git a/library/think/debug/Console.php b/library/think/debug/Console.php
index 6933d5af..f938dd2f 100644
--- a/library/think/debug/Console.php
+++ b/library/think/debug/Console.php
@@ -53,7 +53,7 @@ class Console
             return false;
         }
         // 获取基本信息
-        $runtime = number_format(microtime(true), 8, '.', '') - THINK_START_TIME;
+        $runtime = round(microtime(true) - THINK_START_TIME, 20);
         $reqs    = number_format(1 / $runtime, 2);
         $mem     = number_format((memory_get_usage() - THINK_START_MEM) / 1024, 2);
 
diff --git a/library/think/debug/Html.php b/library/think/debug/Html.php
index a1d42fb5..670aa24d 100644
--- a/library/think/debug/Html.php
+++ b/library/think/debug/Html.php
@@ -53,7 +53,7 @@ class Html
             return false;
         }
         // 获取基本信息
-        $runtime = number_format(microtime(true), 8, '.', '') - THINK_START_TIME;
+        $runtime = round(microtime(true) - THINK_START_TIME, 20);
         $reqs    = number_format(1 / $runtime, 2);
         $mem     = number_format((memory_get_usage() - THINK_START_MEM) / 1024, 2);