The risk of HIV infection among homosexuals is relatively high, especially among gay men. The way gay men have sex is mainly anal sex, and the anus, because the local tissue is dry and does not secrete fluid, can easily lead to local skin breakage during sex, thus allowing HIV to enter the body and cause infection. In addition, many homosexual patients have multiple sexual partners, so promiscuity is also one of the high-risk factors for AIDS. The most important ways of HIV transmission are blood transmission, sexual contact transmission and vertical transmission from mother to child, currently sexual contact transmission is the most important way of transmission, normal people need to be clean and need to have a fixed sexual partner.