Asking to get Visit Visa from Iran to china for me and family

You may just apply for the China visa from the China Emabssy in tehran, since you are holding Iran residence visa. The documents to tbe submitted include your valid passport with more than 6 months validity left and adequate blank pages, a completely filled visa application form each with your genuine information, a passport sized photo, your Iran residence visas and round-trip air tickets.
Additional documents may be required by the embassy, such as financial proof and Original NBI clearance valid for travel abroad.