diff --git a/dsSupport/Business/Preview/PreviewController/PreviewController.go b/dsSupport/Business/Preview/PreviewController/PreviewController.go
index 0a02a7b9..c370ee9e 100644
--- a/dsSupport/Business/Preview/PreviewController/PreviewController.go
+++ b/dsSupport/Business/Preview/PreviewController/PreviewController.go
@@ -1,6 +1,7 @@
 package PreviewController
 
 import (
+	"dsSupport/Const"
 	"dsSupport/Utils/CommonUtil"
 	"dsSupport/Utils/ObsUtil"
 	"encoding/base64"
@@ -53,7 +54,7 @@ func previewOffice(c *gin.Context) {
 		return
 	}
 	//将文件上传到华为云
-	key := "dsMinPreview/" + p
+	key := Const.PreviewPrefix + p
 	ObsUtil.UploadFileMultiPart(key, fullPath)
 	//返回地址
 	url := "http://ow365.cn/?i=14531&fname=" + p + "&furl=http%3A%2F%2Fvideo.edusoa.com%2F" + key
diff --git a/dsSupport/Const/Const.go b/dsSupport/Const/Const.go
new file mode 100644
index 00000000..1dfd6335
--- /dev/null
+++ b/dsSupport/Const/Const.go
@@ -0,0 +1,3 @@
+package Const
+
+const PreviewPrefix = "dsMinPreview/"
diff --git a/dsSupport/CronTask/CleanPreviewFile.go b/dsSupport/CronTask/CleanPreviewFile.go
index 4701606c..ef39b63c 100644
--- a/dsSupport/CronTask/CleanPreviewFile.go
+++ b/dsSupport/CronTask/CleanPreviewFile.go
@@ -1,10 +1,11 @@
 package CronTask
 
 import (
-	"fmt"
-	"time"
+	"dsSupport/Const"
+	"dsSupport/Utils/ObsUtil"
 )
 
-func Task (){
-	fmt.Println("hello world", time.Now())
-}
\ No newline at end of file
+func Task() {
+	//删除7天前上传的文件
+	ObsUtil.DeleteExpireFile(Const.PreviewPrefix, 7)
+}