diff --git a/yudao-module-bpm/yudao-module-bpm-biz/src/main/java/cn/iocoder/yudao/module/bpm/framework/flowable/core/behavior/BpmActivityBehaviorFactory.java b/yudao-module-bpm/yudao-module-bpm-biz/src/main/java/cn/iocoder/yudao/module/bpm/framework/flowable/core/behavior/BpmActivityBehaviorFactory.java
index e9f1f32d7..b5278f5ab 100644
--- a/yudao-module-bpm/yudao-module-bpm-biz/src/main/java/cn/iocoder/yudao/module/bpm/framework/flowable/core/behavior/BpmActivityBehaviorFactory.java
+++ b/yudao-module-bpm/yudao-module-bpm-biz/src/main/java/cn/iocoder/yudao/module/bpm/framework/flowable/core/behavior/BpmActivityBehaviorFactory.java
@@ -6,6 +6,7 @@ import org.flowable.bpmn.model.Activity;
 import org.flowable.bpmn.model.UserTask;
 import org.flowable.engine.impl.bpmn.behavior.AbstractBpmnActivityBehavior;
 import org.flowable.engine.impl.bpmn.behavior.ParallelMultiInstanceBehavior;
+import org.flowable.engine.impl.bpmn.behavior.SequentialMultiInstanceBehavior;
 import org.flowable.engine.impl.bpmn.behavior.UserTaskActivityBehavior;
 import org.flowable.engine.impl.bpmn.parser.factory.DefaultActivityBehaviorFactory;
 
@@ -28,11 +29,16 @@ public class BpmActivityBehaviorFactory extends DefaultActivityBehaviorFactory {
 
     @Override
     public ParallelMultiInstanceBehavior createParallelMultiInstanceBehavior(Activity activity,
-                                                                             AbstractBpmnActivityBehavior innerActivityBehavior) {
-        return new BpmParallelMultiInstanceBehavior(activity, innerActivityBehavior)
+                                                                             AbstractBpmnActivityBehavior behavior) {
+        return new BpmParallelMultiInstanceBehavior(activity, behavior)
                 .setTaskCandidateInvoker(taskCandidateInvoker);
     }
 
-    // TODO @ke：SequentialMultiInstanceBehavior 这个抽空也可以看看
+    @Override
+    public SequentialMultiInstanceBehavior createSequentialMultiInstanceBehavior(Activity activity,
+                                                                                 AbstractBpmnActivityBehavior behavior) {
+        return new BpmSequentialMultiInstanceBehavior(activity, behavior)
+                .setTaskCandidateInvoker(taskCandidateInvoker);
+    }
 
 }
diff --git a/yudao-module-bpm/yudao-module-bpm-biz/src/main/java/cn/iocoder/yudao/module/bpm/framework/flowable/core/behavior/BpmParallelMultiInstanceBehavior.java b/yudao-module-bpm/yudao-module-bpm-biz/src/main/java/cn/iocoder/yudao/module/bpm/framework/flowable/core/behavior/BpmParallelMultiInstanceBehavior.java
index ed51b23fa..938d04ed1 100644
--- a/yudao-module-bpm/yudao-module-bpm-biz/src/main/java/cn/iocoder/yudao/module/bpm/framework/flowable/core/behavior/BpmParallelMultiInstanceBehavior.java
+++ b/yudao-module-bpm/yudao-module-bpm-biz/src/main/java/cn/iocoder/yudao/module/bpm/framework/flowable/core/behavior/BpmParallelMultiInstanceBehavior.java
@@ -3,7 +3,6 @@ package cn.iocoder.yudao.module.bpm.framework.flowable.core.behavior;
 import cn.iocoder.yudao.framework.flowable.core.util.FlowableUtils;
 import cn.iocoder.yudao.module.bpm.framework.flowable.core.candidate.BpmTaskCandidateInvoker;
 import lombok.Setter;
-import lombok.extern.slf4j.Slf4j;
 import org.flowable.bpmn.model.Activity;
 import org.flowable.engine.delegate.DelegateExecution;
 import org.flowable.engine.impl.bpmn.behavior.AbstractBpmnActivityBehavior;
@@ -17,12 +16,11 @@ import java.util.Set;
  * 第二步，将【多个】任务候选人们，设置到 DelegateExecution 的 collectionVariable 变量中，以便 BpmUserTaskActivityBehavior 使用它
  *
  * @author kemengkai
- * @date 2022-04-21 16:57
+ * @since 2022-04-21 16:57
  */
-@Slf4j
+@Setter
 public class BpmParallelMultiInstanceBehavior extends ParallelMultiInstanceBehavior {
 
-    @Setter
     private BpmTaskCandidateInvoker taskCandidateInvoker;
 
     public BpmParallelMultiInstanceBehavior(Activity activity,
diff --git a/yudao-module-bpm/yudao-module-bpm-biz/src/main/java/cn/iocoder/yudao/module/bpm/framework/flowable/core/behavior/BpmSequentialMultiInstanceBehavior.java b/yudao-module-bpm/yudao-module-bpm-biz/src/main/java/cn/iocoder/yudao/module/bpm/framework/flowable/core/behavior/BpmSequentialMultiInstanceBehavior.java
new file mode 100644
index 000000000..1e4ebc141
--- /dev/null
+++ b/yudao-module-bpm/yudao-module-bpm-biz/src/main/java/cn/iocoder/yudao/module/bpm/framework/flowable/core/behavior/BpmSequentialMultiInstanceBehavior.java
@@ -0,0 +1,50 @@
+package cn.iocoder.yudao.module.bpm.framework.flowable.core.behavior;
+
+import cn.iocoder.yudao.framework.flowable.core.util.FlowableUtils;
+import cn.iocoder.yudao.module.bpm.framework.flowable.core.candidate.BpmTaskCandidateInvoker;
+import lombok.Setter;
+import org.flowable.bpmn.model.Activity;
+import org.flowable.engine.delegate.DelegateExecution;
+import org.flowable.engine.impl.bpmn.behavior.AbstractBpmnActivityBehavior;
+import org.flowable.engine.impl.bpmn.behavior.SequentialMultiInstanceBehavior;
+
+import java.util.LinkedHashSet;
+import java.util.Set;
+
+/**
+ * 自定义的【串行】的【多个】流程任务的 assignee 负责人的分配
+ *
+ * 本质上，实现和 {@link BpmParallelMultiInstanceBehavior} 一样，只是继承的类不一样
+ *
+ * @author 芋道源码
+ */
+@Setter
+public class BpmSequentialMultiInstanceBehavior extends SequentialMultiInstanceBehavior {
+
+    private BpmTaskCandidateInvoker taskCandidateInvoker;
+
+    public BpmSequentialMultiInstanceBehavior(Activity activity, AbstractBpmnActivityBehavior innerActivityBehavior) {
+        super(activity, innerActivityBehavior);
+    }
+
+    /**
+     * 逻辑和 {@link BpmParallelMultiInstanceBehavior#resolveNrOfInstances(DelegateExecution)} 类似
+     *
+     * 差异的点：是在【第二步】的时候，需要返回 LinkedHashSet 集合！因为它需要有序！
+     */
+    @Override
+    protected int resolveNrOfInstances(DelegateExecution execution) {
+        // 第一步，设置 collectionVariable 和 CollectionVariable
+        // 从  execution.getVariable() 读取所有任务处理人的 key
+        super.collectionExpression = null; // collectionExpression 和 collectionVariable 是互斥的
+        super.collectionVariable = FlowableUtils.formatCollectionVariable(execution.getCurrentActivityId());
+        // 从 execution.getVariable() 读取当前所有任务处理的人的 key
+        super.collectionElementVariable = FlowableUtils.formatCollectionElementVariable(execution.getCurrentActivityId());
+
+        // 第二步，获取任务的所有处理人
+        Set<Long> assigneeUserIds = new LinkedHashSet<>(taskCandidateInvoker.calculateUsers(execution)); // 保证有序！！！
+        execution.setVariable(super.collectionVariable, assigneeUserIds);
+        return assigneeUserIds.size();
+    }
+
+}
diff --git a/yudao-module-bpm/yudao-module-bpm-biz/src/main/java/cn/iocoder/yudao/module/bpm/framework/flowable/core/behavior/BpmUserTaskActivityBehavior.java b/yudao-module-bpm/yudao-module-bpm-biz/src/main/java/cn/iocoder/yudao/module/bpm/framework/flowable/core/behavior/BpmUserTaskActivityBehavior.java
index de17502bf..c49465273 100644
--- a/yudao-module-bpm/yudao-module-bpm-biz/src/main/java/cn/iocoder/yudao/module/bpm/framework/flowable/core/behavior/BpmUserTaskActivityBehavior.java
+++ b/yudao-module-bpm/yudao-module-bpm-biz/src/main/java/cn/iocoder/yudao/module/bpm/framework/flowable/core/behavior/BpmUserTaskActivityBehavior.java
@@ -47,7 +47,8 @@ public class BpmUserTaskActivityBehavior extends UserTaskActivityBehavior {
     }
 
     private Long calculateTaskCandidateUsers(DelegateExecution execution) {
-        // 情况一，如果是多实例的任务，例如说会签、或签等情况，则从 Variable 中获取。它的任务处理人在 BpmParallelMultiInstanceBehavior 中已经被分配了
+        // 情况一，如果是多实例的任务，例如说会签、或签等情况，则从 Variable 中获取。
+        // 顺序审批可见 BpmSequentialMultiInstanceBehavior，并发审批可见 BpmSequentialMultiInstanceBehavior
         if (super.multiInstanceActivityBehavior != null) {
             return execution.getVariable(super.multiInstanceActivityBehavior.getCollectionElementVariable(), Long.class);
         }