diff --git a/snail-job-server/snail-job-server-job-task/src/main/java/com/aizuda/snailjob/server/job/task/support/generator/task/MapReduceTaskGenerator.java b/snail-job-server/snail-job-server-job-task/src/main/java/com/aizuda/snailjob/server/job/task/support/generator/task/MapReduceTaskGenerator.java
index 548899e0..a69a27fa 100644
--- a/snail-job-server/snail-job-server-job-task/src/main/java/com/aizuda/snailjob/server/job/task/support/generator/task/MapReduceTaskGenerator.java
+++ b/snail-job-server/snail-job-server-job-task/src/main/java/com/aizuda/snailjob/server/job/task/support/generator/task/MapReduceTaskGenerator.java
@@ -99,7 +99,7 @@ public class MapReduceTaskGenerator extends AbstractJobTaskGenerator {
         jobTask.setArgsType(context.getArgsType());
         JobArgsHolder jobArgsHolder = new JobArgsHolder();
         jobArgsHolder.setJobParams(context.getArgsStr());
-        jobArgsHolder.setReduces(JsonUtil.toJsonString(StreamUtils.toSet(jobTasks, JobTask::getResultMessage)));
+        jobArgsHolder.setReduces(JsonUtil.toJsonString(StreamUtils.toList(jobTasks, JobTask::getResultMessage)));
         jobTask.setArgsStr(JsonUtil.toJsonString(jobArgsHolder));
         jobTask.setTaskStatus(JobTaskStatusEnum.RUNNING.getStatus());
         jobTask.setResultMessage(Optional.ofNullable(jobTask.getResultMessage()).orElse(StrUtil.EMPTY));