Contacted oneplus.cn, and their reply as below.
Dear Oneplus Fan,
Please confirm your phone's version(international or Chinese ):
1. If international one,please contact our overseas service via ①Mail: support@oneplus.net ; ②Facebook: https://www.facebook.com/oneplusofficial.
2. If Chinese one, regret to say that we cannot receive international express currently. You can send your phone to your Chinese friends or relatives and entrust them to repair. They can contact 4008881111 so that our service center will guide your entruster to solve your case.
Best Regards,
OnePlus Service Support Team
So I guessed I can't do anything with my OPO now..