i am pakistani and i want china visa

Do you mean you want to study in China? If so, you need to be enrolled by a school in China first, and then the school will manage some student visa requirements for you like JW201 or JW202 and admission notice. Besides these requirements, you also need to submit these following documents to China embassy to obtain an student visa: your passport and one recent passport photo, visa application forms V2011A and V2011B, your local police character/clearance certificate, Secondary School Certificate Examination Marks and Physical Examination Record for Foreigner attested by the Ministry of Foreign Affairs of Pakistan.
After arrival in China within 30 days, you need to go to local PSB to change this student visa to a tempoary resident permit.