How to change the password for game center?

Hello XuanPhuocTang,

It sounds like you would like to change the password that you use for Game Center. This password is the same as the one that you use for your Apple ID in general, so here is the article for changing your Apple ID password. Which you can then update in Settings > Game Center once it is changed.

Apple ID: Changing your password

http://support.apple.com/kb/ht5624

Keep in mind that if you change your password, you may also need to update it for the other services on your iPad:

Apple ID: What to do after you change your Apple ID

http://support.apple.com/kb/HT5796

Thank you for using Apple Support Communities.

Take care,

Sterling