You should start processing now. And you need to provide following documents:
1. Application form;
2. Your passport valid for at least six months with at least 2 blank visa pages.
3. One recent passport size photograph.
4. One Passport photocopy.
5. Covering letter from applicant's company or employer addressed to the visa office.
6. Photocopy of a confirmed return air ticket
7. Visiting relatives should have invitation from their relatives in China and photocopies of their relatives' Residence Permits in China.
8. You may be requested to supply proof of travel expenses.