What are the documents needed for tourist visa?

You are required to provide:
1. your passport (with the validity of six months and two blank pages at least)
2. filled application form affixed with a recent passport size photo
3. the invitation letter from Chinese individual or any authorized companies, organizations etc.

If you don't have the invitation letter, you should provide round-trip air tickets, hotel booking and travel itinerary. Sometimes, some nationals are required to provide the travel issurance (probably 100 USD per day).