Want to apply China's Visa for my parents and younger sister

First, prepare the relevant materials including passport and its copy, the application form, passport-style photos, valid registration form of temporary residence, an invitation letter from your school, and an invitation letter from you, copies of your passport and Chinese residence permit, your relationship evidence. Next, submit the application to Chinese embassy to apply for S2 type.

thanku for such a good answer. could you please elaborate the documents named valid registeration form of temporary residence, invitation letter from school, invitation letter from me? i never heard about these documents. thank you

You can find the invitation letter samples at this website. You can download it and then ask your school to fill it out; afterwards, print the invitation out for your own use.