Mr.S Rasool, the invitation letter from the company in China is not sufficient for business visa application, the requirements for business visa application are:
(I) Original Visa Notice Sheet from an authorized governmental apparatus /organization inChina prescribing the visa validity, number of entries and stay period; the company in China can help you to apply for it.

(II) Fully completed Visa Application Form in Chinese or English, attached with one of the applicant's recent color photograph (30mm X 40mm)

(III) Original passport with validity more than six months and minimum 2 blank visa pages;

(IV) Photocopy of the first 2 pages (personal information) of the passport and the recent Chinese visa page if there is any;

(V) Invitation letter from the company/organization/institution you want to visit inChina;