Information on Family visit visa

Hello ,
I need some information urgently . I am a pakistani passport holder. I want to apply for family visit visa to visit my wife (Chinese National).
Please advice me ,except marriage certificate what other documents are required to get it. I am in Pakistan now.
Another thing I want to know, I have residence permit of China on study basis but will expire in 15days. Can I apply for family visit L during this period or do I need to wait for expiry of my permit.
Detailed answers will be highly appreciated.
Thanks in advance.