Abstract: Acquired immunodeficiency syndrome (AIDS) is an important public health problem in China. In 2005, the first edition of the guidelines for the diagnosis and treatment of AIDS was formulated by the AIDS Professional Group of Society of Infectious Diseases of Chinese Medical Association, which was updated in 2011 and 2015, respectively. The fourth edition of the guidelines in 2018 is revised on the basis of the third edition and updated according to national clinical practice and the latest research results. The new research progress in opportunistic infections and human immunodeficency virus(HIV) associated cancers, antiretroviral therapy, HIV post-exposure prophylaxis, and prevention of mother to child transmission were updated in these guidelines. In the 2018 edition, pre-exposure prophylaxis is mentioned for the first time. The strategy of whole course management of HIV infection is put forward and how to do the whole course management of HIV infection is detailed in this version. These guidelines will be updated regularly according to the latest clinical evidence.