AIDS is a chronic infectious disease caused by human immunodeficiency virus infection, which is mainly transmitted through unclean sexual contact and contact with blood and body fluids, and the chances of HIV infection among men who have sex with men are higher, mainly due to the following reasons. First, body fluids contain a certain amount of HIV, but the amount of HIV in semen is higher than in other body fluids, especially in vaginal secretions, so the infection rate of men who have sex with men is higher than the infection rate of men who have sex with women. Secondly, in the process of male-to-male sex, there is a possibility of contact with the mucous membrane of the anal skin, which is more likely to cause virus infection and further lead to HIV infection due to the looseness of the local mucosal columnar epithelium. Therefore, in order to better prevent the infection of AIDS, we should pay attention to avoid bad life behavior.