Tudou client cannot download videos. You can uninstall and reinstall the latest version. If you still can't download, try another time. Sometimes it's a server problem.
In addition, you can also use third-party software to download. Such as Weitang.
1. Enter Weitang software and click New.
2. Copy the web address of Tudou online video playback, paste it into Weitang, and confirm to download.
3. Similar third-party software also includes Shuo Mouse. Common video websites, such as Youku, Tudou, Ku6, CNTV, etc., can be downloaded.