You need the following documents to apply for a China Z work visa.
(I) Original Visa Notice Sheet from an authorized governmental apparatus /organization inChina;
(II) Alien Employment License of the P. R. China /Working Permit by the State Administration of Foreign Experts Affairs, P.R. China /Letter of Invitation for Foreigners Engaged in Offshore Petroleum Operations in the P.R. China/Registration Certificate of Foreign Enterprises Permanent Office inChina
(III) Physical Examination Record for Foreigner (the blank form can be downloaded from this website) and attested by Ministry of Foreign Affairs of Pakistan
(IV) Original passport with validity more than six months and minimum 2 blank visa pages;
(V) Photocopy of the first 2 pages (personal information) of the passport and the recent Chinese visa page if there is any;
(VI) Fully completed Visa Application Form in Chinese or English, attached with one of the applicant's recent color photograph (30mm X 40mm)
(VII) Employment Contract
(VIII) Your Employer's Company Registration Certificate in China (copy)