Hello Fengming. Tony, is once again right! Blacklisted devices with icloud Lock cannot be unlocked. This is only possible with the help of the original owner. The only service that we can provide you, is the iCloud Contract Information service, which will provide you all available contact information of the original owner, so you can reach him/her and ask him/her to remove the iCloud Lock from that iPhone!

You cannot unlock an iCloud locked iPhone - the only fix is to get the original owner to delete it in iTunes or replace the logic board