diff --git a/BBWYB.Server.Business/TimeLimitTask/TimeLimitRules.cs b/BBWYB.Server.Business/TimeLimitTask/TimeLimitRules.cs
index fd19236..3fc4d9f 100644
--- a/BBWYB.Server.Business/TimeLimitTask/TimeLimitRules.cs
+++ b/BBWYB.Server.Business/TimeLimitTask/TimeLimitRules.cs
@@ -14,7 +14,7 @@ namespace BBWYB.Server.Business
         {
             calculateExpirationTimeAlgorithmDictionary = new Dictionary<Enums.TimeLimitTaskType, Func<DateTime, DateTime>>()
             {
-                { Enums.TimeLimitTaskType.采购任务, CalculateExpirationTimeFor8WorkHour },
+                { Enums.TimeLimitTaskType.采购任务, CalculateExpirationTimeFor5WorkHour },
                 { Enums.TimeLimitTaskType.合格证拟定任务, CalculateExpirationTimeFor8WorkHour },
                 { Enums.TimeLimitTaskType.待核算任务, CalculateExpirationTimeFor8WorkHour },
                 { Enums.TimeLimitTaskType.待议价任务, CalculateExpirationTimeFor8WorkHour },
@@ -171,6 +171,54 @@ namespace BBWYB.Server.Business
             return startTime.Date.AddDays(addDay).AddHours(addHour).AddSeconds(addSeconds);
         }
 
+        private DateTime CalculateExpirationTimeFor5WorkHour(DateTime startTime)
+        {
+            int addDay = 0, addHour = 0, addSeconds = 0;
+            //先确定是否为周日
+            if (startTime.DayOfWeek == DayOfWeek.Sunday)
+            {
+                addDay = 1;
+                addHour = 14;
+            }
+            else
+            {
+                if (startTime.Hour < 9)
+                    addHour = 14;
+                else if (startTime.Hour >= 9 && startTime.Hour < 12)
+                {
+                    addHour = 13;
+                    var to12senconds = Convert.ToInt32((startTime.Date.AddHours(12) - startTime).TotalSeconds);
+                    addSeconds = 18000 - to12senconds;
+                }
+                else if (startTime.Hour >= 12 && startTime.Hour < 13)
+                {
+                    addHour = 18;
+                }
+                else if (startTime.Hour >= 13 && startTime.Hour < 18)
+                {
+                    if (startTime.Hour == 13 && startTime.Minute <= 5)
+                    {
+                        //从16点开始小于5分钟以内,以当天18点结束
+                        addHour = 18;
+                    }
+                    else
+                    {
+                        addDay = CalculateAddDay(startTime.DayOfWeek);
+                        addHour = 9;
+                        var to18senconds = Convert.ToInt32((startTime.Date.AddHours(18) - startTime).TotalSeconds);
+                        addSeconds = 18000 - to18senconds;
+                    }
+                }
+                else if (startTime.Hour >= 18)
+                {
+                    //下一个工作日的18点结束
+                    addDay = CalculateAddDay(startTime.DayOfWeek);
+                    addHour = 14;
+                }
+            }
+            return startTime.Date.AddDays(addDay).AddHours(addHour).AddSeconds(addSeconds);
+        }
+
         /// <summary>
         /// 计算剩余任务时间(秒)
         /// </summary>