China is facing a major crisis because of the increasing epidemic of HIV/AIDS, especially in the western areas. The purpose of this paper is to enhance understanding of the crisis by analysing the published literature on the epidemiology, demographic features, routes of infection, and risk factors of HIV/AIDS infection in the 12 provinces in the west of China. HIV/AIDS has increased rapidly in recent years. The situation is urgent and requires comprehensive action. China's health care system is decentralized and under-funded, and access to treatment by the poor is seriously limited. There is a lack of knowledge about HIV/AIDS in the general public and health care workers. The HIV/AIDS epidemic emerged initially in western areas of the country by means of intravenous drug use, but sexual risk behaviour and mother-to-child transmissions in the west of China are becoming important for HIV transmission.