diff --git a/module/metric/calc/system/time/avg_of_release_story_delivery_time.php b/module/metric/calc/system/time/avg_of_release_story_delivery_time.php
new file mode 100644
index 0000000000..e319882c5b
--- /dev/null
+++ b/module/metric/calc/system/time/avg_of_release_story_delivery_time.php
@@ -0,0 +1,50 @@
+<?php
+class avg_of_release_story_delivery_time extends baseCalc
+{
+    public $dataset = 'getAllDevStories';
+
+    public $fieldList = array('t1.closedDate', 't1.closedReason', 't1.releasedDate', 't1.openedDate');
+
+    public $result = array();
+
+    public function calculate($row)
+    {
+        $releasedDate = $row->releasedDate;
+        $openedDate   = $row->openedDate;
+        $closedDate   = $row->closedDate;
+
+        if(helper::isZeroDate($closedDate) && helper::isZeroDate($releasedDate)) return;
+        // 如果关闭且关闭原因为已完成，没有发布时间，该需求为直接关闭跳过了中间流程，此时用关闭时间作为发布时间
+        if(!helper::isZeroDate($closedDate) && $closedReason == 'done' && helper::isZeroDate($releasedDate)) $releasedDate = $closedDate;
+
+        $year  = $this->getYear($releasedDate);
+        $month = substr($releasedDate, 5, 2);
+
+        $date1 = new DateTime($releasedDate);
+        $date2 = new DateTime($openedDate);
+
+        $days = $date1->diff($date2)->days;
+
+        if(!isset($this->result[$year])) $this->result[$year] = array();
+        if(!isset($this->result[$year][$month])) $this->result[$year][$month] = array('count' => 0, 'days' => 0);
+
+        $this->result[$year][$month]['count'] ++;
+        $this->result[$year][$month]['days']  += $days;
+    }
+
+    public function getResult($options = array())
+    {
+        $records = array();
+        foreach($this->result as $year => $monthInfo)
+        {
+            foreach($monthInfo as $month => $info)
+            {
+                $record = array('year' => $year, 'month' => $month);
+                $record['value'] = $info['count'] ? round($info['days'] / $info['count'], 4) : 0;
+
+                $records[] = $record;
+            }
+        }
+        return $this->filterByOptions($records, $options);
+    }
+}