diff --git a/BBWY.Server.Business/EvaluationAssistant/EvaluationAssistantBusiness.cs b/BBWY.Server.Business/EvaluationAssistant/EvaluationAssistantBusiness.cs
index 7a6993de..a5f8ac59 100644
--- a/BBWY.Server.Business/EvaluationAssistant/EvaluationAssistantBusiness.cs
+++ b/BBWY.Server.Business/EvaluationAssistant/EvaluationAssistantBusiness.cs
@@ -322,7 +322,47 @@ namespace BBWY.Server.Business
                 CheckSkuRepeat(pt, nextPromotionTaskList);
             }
 
-            fsql.Update<PromotionTask>(request.TaskId).Set(pt1 => pt1.PreTaskId, request.PreTaskId).ExecuteAffrows();
+
+            #region 清空后代
+            var waitList = fsql.Select<PromotionTask>().Where(pt1 => pt1.ShopId == pt.ShopId &&
+                                                                     pt1.Id != pt.Id &&
+                                                                     pt1.PreTaskId != null &&
+                                                                     pt1.Status == Enums.PromitionTaskStatus.等待).ToList(pt1 => new PromotionTask { Id = pt1.Id, PreTaskId = pt1.PreTaskId });
+
+            var childIdList = GetChildTaskIdList(pt.Id, waitList, null);
+            #endregion
+
+            fsql.Transaction(() =>
+            {
+                fsql.Update<PromotionTask>(request.TaskId).Set(pt1 => pt1.PreTaskId, request.PreTaskId).ExecuteAffrows();
+                if (childIdList.Count() > 0)
+                    fsql.Update<PromotionTask>(childIdList.ToArray()).Set(pt1 => pt1.PreTaskId, null).ExecuteAffrows();
+            });
+
+        }
+
+        /// <summary>
+        /// 递归找子级任务
+        /// </summary>
+        /// <param name="taskId"></param>
+        /// <param name="waitList"></param>
+        /// <param name="childIdList"></param>
+        /// <returns></returns>
+        public IList<long> GetChildTaskIdList(long taskId, IList<PromotionTask> waitList, IList<long> childIdList)
+        {
+            if (childIdList == null)
+                childIdList = new List<long>();
+
+            var childTaskList = waitList.Where(w => w.PreTaskId == taskId).ToList();
+            if (childTaskList.Count() != 0)
+            {
+                foreach (var childTask in childTaskList)
+                {
+                    childIdList.Add(childTask.Id);
+                    GetChildTaskIdList(childTask.Id, waitList, childIdList);
+                }
+            }
+            return childIdList;
         }
 
         private void CheckSkuRepeat(PromotionTask pt, IList<PromotionTask> waitCheckList)