when I try to open my web, the page always redirected to 403 error page.

403 Forbidden!

The address you have entered is not open to the public,
(This may be caused by not having a index.html file in your root directory).

My web do have index.html file

my domain name:
Custom Domain: fatu.cn
Sub domain :http://jiawo8.zxq.net

your index.html file has to be in the root '/' folder or the first folder your FTP Client connects to. now if you have it in a folder called htdocs, then it will be jiawo8.zxq.net/htdocs/index.html

There is a folder called www, my index.html file is in this folder.
jiawo8.zxq.net/www/index.html

move the index.html from there to your ROOT '/' and then it will be jiawo8.zxq.net/index.html and NOT jiawo8.zxq.net/www/index.html

it works. Thank you very much.