diff --git a/module/story/model.php b/module/story/model.php
index bd7fe42f37..c9106a7dd2 100644
--- a/module/story/model.php
+++ b/module/story/model.php
@@ -86,11 +86,11 @@ class storyModel extends model
         $story->children = array();
         if($story->parent == '-1') $story->children = $this->dao->select('*')->from(TABLE_STORY)->where('parent')->eq($storyID)->andWhere('deleted')->eq(0)->fetchAll('id');
 
-        $story->openedDate    = substr($story->openedDate, 0, 19);
-        $story->assignedDate  = substr($story->assignedDate, 0, 19);
-        $story->reviewedDate  = substr($story->reviewedDate, 0, 19);
-        $story->closedDate    = substr($story->closedDate, 0, 19);
-        $story->lastEditedDate= substr($story->lastEditedDate, 0, 19);
+        $story->openedDate    = empty($story->openedDate)    ? '' : substr($story->openedDate,     0, 19);
+        $story->assignedDate  = empty($story->assignedDate)  ? '' : substr($story->assignedDate,   0, 19);
+        $story->reviewedDate  = empty($story->reviewedDate)  ? '' : substr($story->reviewedDate,   0, 19);
+        $story->closedDate    = empty($story->closedDate)    ? '' : substr($story->closedDate,     0, 19);
+        $story->lastEditedDate= empty($story->lastEditedDate)? '' : substr($story->lastEditedDate, 0, 19);
 
         return $story;
     }
@@ -1423,16 +1423,15 @@ class storyModel extends model
      * @access public
      * @return bool
      */
-    public function computeEstimate($storyID)
+    public function computeEstimate(int $storyID): bool
     {
         if(!$storyID) return true;
 
-        $stories = $this->dao->select('`id`,`estimate`,status')->from(TABLE_STORY)->where('parent')->eq($storyID)->andWhere('deleted')->eq(0)->fetchAll('id');
-        if(empty($stories)) return true;
+        $estimates = $this->dao->select('`id`,`estimate`')->from(TABLE_STORY)->where('parent')->eq($storyID)->andWhere('deleted')->eq(0)->fetchPairs('id', 'estimate');
+        if(empty($estimates)) return true;
 
-        $estimate = 0;
-        foreach($stories as $story) $estimate += $story->estimate;
-        $this->dao->update(TABLE_STORY)->set('estimate')->eq($estimate)->autoCheck()->where('id')->eq($storyID)->exec();
+        $estimate = round(array_sum($estimates), 2);
+        $this->dao->update(TABLE_STORY)->set('estimate')->eq($estimate)->where('id')->eq($storyID)->exec();
         return !dao::isError();
     }
 
diff --git a/module/story/test/model/computeestimate.php b/module/story/test/model/computeestimate.php
index 1a328e1c7a..afd7d398b1 100755
--- a/module/story/test/model/computeestimate.php
+++ b/module/story/test/model/computeestimate.php
@@ -4,6 +4,11 @@ include dirname(__FILE__, 5) . '/test/lib/init.php';
 include dirname(__FILE__, 2) . '/story.class.php';
 su('admin');
 
+$story = zdTable('story');
+$story->parent->range('0,`-1`,2{3}');
+$story->estimate->range('[1-4]');
+$story->gen(5);
+
 /**
 
 title=测试 storyModel->computeEstimate();
@@ -16,4 +21,8 @@ pid=1
 
 $story = new storyTest();
 
-r() && p() && e();
\ No newline at end of file
+r($story->computeEstimateTest(0))  && p()          && e('0');   //不传入需求。
+r($story->computeEstimateTest(1))  && p('old,new') && e('1,1'); //传入普通需求，检查计算前后预计工时变化。
+r($story->computeEstimateTest(2))  && p('old,new') && e('2,8'); //传入父需求，检查计算前后预计工时变化。
+r($story->computeEstimateTest(3))  && p('old,new') && e('3,3'); //传入子需求，检查计算前后预计工时变化。
+r($story->computeEstimateTest(10)) && p()          && e('0');   //传入不存在的需求。
diff --git a/module/story/test/story.class.php b/module/story/test/story.class.php
index 2222cb58ea..a084184bff 100644
--- a/module/story/test/story.class.php
+++ b/module/story/test/story.class.php
@@ -239,15 +239,19 @@ class storyTest
      *
      * @param  int    $storyID
      * @access public
-     * @return void
+     * @return array
      */
-    public function computeEstimateTest($storyID)
+    public function computeEstimateTest(int $storyID): array
     {
+        $oldStory = $this->objectModel->getByID($storyID);
+        if(empty($oldStory)) return array();
+
         $this->objectModel->computeEstimate($storyID);
 
         if(dao::isError()) return dao::getError();
 
-        return $this->objectModel->getByID($storyID);
+        $newStory = $this->objectModel->getByID($storyID);
+        return array('old' => $oldStory->estimate, 'new' => $newStory->estimate);
     }
 
     /**