diff --git a/docs/docs/en/guide/project/workflow-definition.md b/docs/docs/en/guide/project/workflow-definition.md
index 49b902433f..1dacff17e2 100644
--- a/docs/docs/en/guide/project/workflow-definition.md
+++ b/docs/docs/en/guide/project/workflow-definition.md
@@ -75,8 +75,10 @@ Workflow running parameter description:
 * **Worker grouping**: This process can only be executed in the specified worker machine group. The default is Default, which can be executed on any worker.
 * **Notification Group**: Select Notification Policy||Timeout Alarm||When fault tolerance occurs, process information or emails will be sent to all members in the notification group.
 * **Startup parameters**: Set or override the value of global parameters when starting a new process instance.
-* **Complement(Backfill)**: Run workflow for a specified historical period. There are two strategies: serial complement and parallel complement. 
+* **Complement(Backfill)**: Run workflow for a specified historical period. There are two strategies: serial complement and parallel complement.
+
   > You could select the time period or fill in it manually in UI. The date range is left closed and right closed time interval (startDate <= N <= endDate)
+
   * Serial complement: Run the workflow from start date to end date according to the time period you set in serial.
 
   ![workflow-serial](../../../../img/new_ui/dev/project/workflow-serial.png)
diff --git a/docs/docs/zh/guide/project/workflow-definition.md b/docs/docs/zh/guide/project/workflow-definition.md
index a9eaafa879..77db0dcbcf 100644
--- a/docs/docs/zh/guide/project/workflow-definition.md
+++ b/docs/docs/zh/guide/project/workflow-definition.md
@@ -84,7 +84,9 @@
 * 通知组：选择通知策略||超时报警||发生容错时，会发送流程信息或邮件到通知组里的所有成员。
 * 启动参数: 在启动新的流程实例时，设置或覆盖全局参数的值。
 * 补数：指运行指定日期范围内的工作流定义，根据补数策略生成对应的工作流实例，补数策略包括串行补数、并行补数 2 种模式。
+
   > 日期可以通过页面选择或者手动输入，日期范围是左关右关区间(startDate <= N <= endDate)
+
   * 串行补数：指定时间范围内，从开始日期至结束日期依次执行补数，依次生成多条流程实例；点击运行工作流，选择串行补数模式：例如从7月 9号到7月10号依次执行，依次在流程实例页面生成两条流程实例。
 
   ![workflow-serial](../../../../img/new_ui/dev/project/workflow-serial.png)