diff --git a/oss-service/src/main/java/cn/axzo/oss/service/impl/FileServiceImpl.java b/oss-service/src/main/java/cn/axzo/oss/service/impl/FileServiceImpl.java
index 9dc7ac3..2cfb365 100644
--- a/oss-service/src/main/java/cn/axzo/oss/service/impl/FileServiceImpl.java
+++ b/oss-service/src/main/java/cn/axzo/oss/service/impl/FileServiceImpl.java
@@ -848,7 +848,8 @@ public class FileServiceImpl implements FileService {
             Long expire = bizSceneExpireMap.get(item.getAppChannelBucketNo());
             // bucket下的key
             String tgtFileKey = Utility.generateFileKey(item.getDirectory(), item.getFileUuid(), item.getFileFormat());
-            switch (BucketTypeEnum.getByCode(bucketTypeMap.get(item.getAppChannelBucketNo()))) {
+            String bucketType = StringUtils.isNotBlank(bucketTypeMap.get(item.getAppChannelBucketNo())) ? bucketTypeMap.get(item.getAppChannelBucketNo()) : BucketTypeEnum.PUBLIC_BUCKET.getCode();
+            switch (BucketTypeEnum.getByCode(bucketType)) {
                 case PUBLIC_BUCKET:
                     String url = this.fileManager.fetchDownloadUrl(item.getBucketName(), tgtFileKey, item.getChannelCode());
                     return SignUrlDownloadResponse.builder()