You have to get the Chinese client for mac up to date and follow the manual patching guide. But instead of using the *.exe files in the downloaded archive, use the equivalent files from your Chinese client.
Or use Bootcamp
Edit: I didn't find any downloader for an OSX Chinese client. I don't know mac os at all, but I think there might be some windows emulator you could use, though your game might need more resources to run. I used something similar to play wow on linux. But the best solutions is either Bootcamp, or Taiwan servers because you just need to modify the realmlist.wtf to play there.