diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/plans/distribute/worker/job/UnassignedGatherJob.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/plans/distribute/worker/job/UnassignedGatherJob.java
index 1789eae644852f..9562ef72f664e1 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/plans/distribute/worker/job/UnassignedGatherJob.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/plans/distribute/worker/job/UnassignedGatherJob.java
@@ -22,6 +22,7 @@
 import org.apache.doris.nereids.trees.plans.distribute.worker.DistributedPlanWorker;
 import org.apache.doris.planner.ExchangeNode;
 import org.apache.doris.planner.PlanFragment;
+import org.apache.doris.planner.PlanNode;
 import org.apache.doris.qe.ConnectContext;
 
 import com.google.common.collect.ImmutableList;
@@ -77,6 +78,9 @@ selectedWorker, new DefaultScanSource(ImmutableMap.of())
     }
 
     protected int degreeOfParallelism() {
+        if (fragment.getPlanRoot().anyMatch(p -> ((PlanNode) p).isSerialOperator())) {
+            return 1;
+        }
         return useLocalShuffleToAddParallel ? fragment.getParallelExecNum() : 1;
     }
 }
diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/plans/distribute/worker/job/UnassignedShuffleJob.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/plans/distribute/worker/job/UnassignedShuffleJob.java
index 6513c2b9c41a6e..694981e52dc636 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/plans/distribute/worker/job/UnassignedShuffleJob.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/plans/distribute/worker/job/UnassignedShuffleJob.java
@@ -89,6 +89,10 @@ protected int degreeOfParallelism() {
             expectInstanceNum = ConnectContext.get().getSessionVariable().getExchangeInstanceParallel();
         }
 
+        if (fragment.getPlanRoot().anyMatch(p -> ((PlanNode) p).isSerialOperator())) {
+            return 1;
+        }
+
         // TODO: check nested loop join do right outer / semi / anti join
         return expectInstanceNum;
     }