i want to apply for a nigeria visa for my girl friend here in china, how do i go about it?

You need to go to the nigeria embassy in China to submit the following requirements to obtain a nigeria tourist visa. Also, your GF may attend an interview.
1.Formal invitation letter (original)
2.Copy of inviter's Company Registration in Nigeria if any
3.Two Copies of inviter's International passport or CERPAC Card (Green Card)
4.Copy of Applicant's International Passport Data Page
5.Online Visa Application Form (with one recent passport photograph attached)
6.Documentary evidence of online payment
7.Possession of return air tickets / itinerary
8.Evidence of hotel reservation / accomodation
9. Other deemed necessary requirements by the embassy.