diff --git a/data/src/main/java/com/sdm/data/service/impl/MinioFileIDataFileServiceImpl.java b/data/src/main/java/com/sdm/data/service/impl/MinioFileIDataFileServiceImpl.java
index a672e2f5..658d4e23 100644
--- a/data/src/main/java/com/sdm/data/service/impl/MinioFileIDataFileServiceImpl.java
+++ b/data/src/main/java/com/sdm/data/service/impl/MinioFileIDataFileServiceImpl.java
@@ -1842,7 +1842,7 @@ public class MinioFileIDataFileServiceImpl implements IDataFileService {
                 }
             });
             String resultStr = sb.toString();
-            resultStr.substring(0, resultStr.length() - 1);
+            resultStr = resultStr.substring(0, resultStr.length() - 1);
             return resultStr;
         } catch (Exception e) {
             CoreLogger.error("getCidFlowReviewer error,param:{},errMsg:{}", JSONObject.toJSONString(flowInfos), e.getMessage());