how to block Chinese spam emails?

The problem with trying to filter/delete any spam is the fact that scammers will change their email address at least daily, so if you block b@bbb.com, tomorrow you'll get tons of stuff from c@ccc.com. The only way to effectively stop such spam is to change your email address.

Having said all that, I do not believe Mail will automatically delete; you can send emails to the trash (or any other folder) though by going to Mail > Preferences > rules.

To be honest, I don't know (I use Mail very little and did not see anything like that in the available rules).