diff --git a/core/phpspider.php b/core/phpspider.php
index b253b97..bff6748 100755
--- a/core/phpspider.php
+++ b/core/phpspider.php
@@ -1831,6 +1831,7 @@ public function get_fields($confs, $html, $url, $page)
                 // 没有设置抽取规则的类型 或者 设置为 xpath
                 if (!isset($conf['selector_type']) || $conf['selector_type']=='xpath') 
                 {
+                    // 如果找不到，返回的是false
                     $values = $this->get_fields_xpath($html, $conf['selector'], $conf['name']);
                 }
                 elseif ($conf['selector_type']=='css') 
diff --git a/core/selector.php b/core/selector.php
index 4d8d001..f17cff4 100644
--- a/core/selector.php
+++ b/core/selector.php
@@ -116,7 +116,9 @@ private static function _xpath_select($html, $selector, $remove = false)
         if ($elements === false)
         {
             self::$error = "the selector in the xpath(\"{$selector}\") syntax errors";
-            return false;
+            // 不应该返回false，因为isset(false)为true，更不能通过 !$values 去判断，因为!0为true，所以这里只能返回null
+            //return false;
+            return null;
         }
 
         $result = array();
@@ -159,7 +161,7 @@ private static function _xpath_select($html, $selector, $remove = false)
         }
         if (empty($result)) 
         {
-            return false;
+            return null;
         }
         // 如果只有一个元素就直接返回string，否则返回数组
         return count($result) > 1 ? $result : $result[0];
@@ -210,14 +212,14 @@ private static function _regex_select($html, $selector, $remove = false)
         if(@preg_match_all($selector, $html, $out) === false)
         {
             self::$error = "the selector in the regex(\"{$selector}\") syntax errors";
-            return false;
+            return null;
         }
         $count = count($out);
         $result = array();
         // 一个都没有匹配到
         if ($count == 0) 
         {
-            return false;
+            return null;
         }
         // 只匹配一个，就是只有一个 ()
         elseif ($count == 2) 
@@ -242,7 +244,7 @@ private static function _regex_select($html, $selector, $remove = false)
         }
         if (empty($result)) 
         {
-            return false;
+            return null;
         }
         
         return count($result) > 1 ? $result : $result[0];