Abstract: Since the discovery of HIV more than two decades ago,scientific progress has been impressive and has dramatically advanced our understanding of HIV infection,from molecular through cellular and then on to systemic pathogenesis,such as the functions of HIV-1 nef gene.However,there is still much to be learned before we fully understand how the host interacts with the virus at molecular level and how immune responses correlate with protection from disease.This review describes our current knowledge of HIV/AIDS with the reference of HIV nef functions and its role in HIV-1 mediated pathogenesis.