diff --git a/backend/routes/videos.js b/backend/routes/videos.js
index d230a81..e69cb02 100644
--- a/backend/routes/videos.js
+++ b/backend/routes/videos.js
@@ -64,7 +64,7 @@ async function getVideoCoverFromVod(fileId) {
 // 生成VOD防盗链签名URL
 // 根据腾讯云文档：https://cloud.tencent.com/document/product/266/14047
 // 签名算法：sign = MD5(KEY + Dir + t + us)
-function generateSignedUrl(videoUrl, signKey, expirationTime = 3600) {
+function generateSignedUrl(videoUrl, signKey, expirationTime = 86400) {
   if (!signKey || !videoUrl) {
     return videoUrl;
   }