The reason why high-risk sex is the main means of transmission of HIV is that the HIV virus, which causes AIDS, is mainly found in the blood, semen, vaginal secretions, chest and abdominal fluids, breast milk and cerebrospinal fluid of people with AIDS and HIV infection. Among these bodily fluids, semen and vaginal secretions are the most easily accessible ones. Therefore, high-risk sex is a common mode of transmission in clinical practice, but if patients take the necessary safety measures, i.e., use condoms, when having sex, it will greatly reduce the risk of HIV infection. Therefore, if patients want to eliminate AIDS, they need to strictly avoid unprotected sex.