i want to vist china for business porpuse ,what are the thing which is required for applying for a China visa?

You should basically submit following documents to Chinese embassy in Islambad:
1. Duly completed Visa Application Form (can be downloaded from this website), affix one recent color photo (30mm X 40mm).
2. Original passport with a validity of more than 6 months and minimum 2 blank visa pages, and photocopies of the first 2 pages (personal information) of your passport and recent Chinese visas if any.
3. If it is your first visit to China, you should provide your local police character/clearance certificate.
4. Your bank statement and round-trip tickets.
For business purpose, you need additional documents:
1. Original invitation or confirmation letter (used to be called Visa Notice) from an authorized government organization like the local foreign affairs office or etc. in China;
2. Invitation letter from your inviting Chinese organization;
3. A recommendation letter from your local Chamber of Commerce & Industry or your company Registration
Certificate (photocopy);
4. A supporting letter from your organization;
5. Your tax certificate (photocopy);
6. Your bank statement (personal or company).
With above documents, you can visit Chinese embassy in person or entrust someone else to apply for a China visa on your behalf. Diplomatic and Official passport holders of the third countries as well as Pakistani ordinary passport holders are exempted from visa fees. Visa processing normally takes 4 working days. Express service takes 2 to 3 working days, extra service fee is required.