can S2 be renewed for six mouth

Hi, it's possible to apply for 6 months S2 type from the China embassy. You can give it a try.

please am already in china and i came with s2 type . it renewable

How much to renew and how long to renew please?

You need to provide passport, a passport-style photo, a completed application form, valid registration form of temporary residence, an invitation letter from your family member and copy of her/his passport, as well as your relationship certificate and others. And then go to the exit and entry administration of the local PSB to renew it. It may cost RMB160 or so.