I am south sudanese national and I want to go to china for holidays,what requirement are need?

You are applying in the US, right? You need the following documents:
(1)your valid passport with at least two blank pages and a validity of 6 months;
(2)Completed 2011A visa application form、V2011B visa application form;
(3)one color photo on the each Application Form. The photo should berecent, front view, in 48mm x33mm size without head covering.
(4)Proof of U.S. Residency Status（a valid U.S. visa or ID, water or electricity bills or tenancy agreement）