You need following documents for business visa application:
1. Original passport remaining to be valid for at least 6 months with a blank visa pages.
2. One completed and truly filled Visa Application Form of China with a recently-taken passport photo;
3. An Invitation Letter from a company or institution in China (The letter of invitation can not be email, and should include full name and passport number of the invitee as well as the purpose and duration of the visit).
4. the original and a copy of your permanent residence which should be valid for at least half a year.