Business visa. I am from pakistan and i want china's business visa

You should provide your passport and copy of its data page, the completed application form attached with 2 passport-style photos, the invitation letter of duly authorized unit, letter of undertaking from your company, tax certificate, copy of your company's business license, bank statement and the invitation letter from the Chinese business partner, as well as other required documents. The application fee would be free of charge.

What if i dont have any invitayion letter ???

You need the invitation letter if you want to apply for business M type.