Although HIV-infected people have the same appearance as normal people, their blood, semen, vaginal secretions, exudate from broken skin mucous membrane or inflammatory ulcers contain a large amount of HIV, which is highly contagious; breast milk also contains virus and is contagious. The virus can also be found in saliva, tears, sweat and urine, but the amount of virus contained is very small and not very contagious, so it can be disregarded. There are three main proven ways of AIDS transmission, the core of which is through sexual transmission and blood transmission, general contact does not transmit AIDS, so AIDS patients should not be discriminated against in their lives, such as eating together, shaking hands, etc. will not transmit AIDS. (1) Sexual contact transmission: including sexual contact between same sex and opposite sex. Anal sex has a greater risk of transmission. (2) Blood transmission: ① importing HIV-contaminated blood or blood products; ② sharing HIV-contaminated, unsterilized needles and syringes among IV drug addicts; ③ sharing other medical equipment or household utensils (e.g. sharing toothbrushes and razors with infected people) may also be transmitted through the breakage, but it is rare. ④Syringes and needles are incompletely sterilized or not sterilized, especially children’s preventive injections are not one person, one needle and one tube; dentistry equipment, delivery equipment, surgical instruments, needles for acupuncture treatment are not tightly sterilized or not sterilized; knives, needles for hairdressing, cosmetology (such as eyebrow tattooing, ear piercing), tattooing, etc., and bathroom pedicure knives are not sterilized; sharing razors, razors, or toothbrushes with other people; transfusion with Blood or blood products from blood donors without HIV antibody test, and similar cases of bone marrow transfusion and organ transfer; rescue of the bleeding wounded, the rescuer’s own broken skin contact with the wounded’s blood. (3) Mother-to-child transmission: Also known as perinatal transmission, this is when an HIV-infected mother transmits HIV to her fetus or baby before, during, and shortly after delivery. Transmission can occur through the placenta, or through the birth canal during delivery, or through breastfeeding. The disease is mainly transmitted through sexual contact, especially homosexuality and intravenous drug use, followed by therapeutic output and injection of blood products, and can also be transmitted through childbirth and breastfeeding. High risk groups include: homosexuals, sexual promiscuity and multiple sexual partners, intravenous drug addicts, recipients of blood transfusions and blood products, hemophiliacs, and children whose parents are AIDS patients. Recently, it is believed that patients with STDs, especially those with genital ulcers (e.g. syphilis, soft chancre, genital herpes) should also be classified as a high-risk group for AIDS. Sexual contact, whether between homosexuals, heterosexuals, or both sexes, can lead to the transmission of AIDS. There is a large amount of virus in the semen or vaginal secretions of HIV-infected people. During sexual activity (including vaginal, anal and oral sex), the friction of the sexual intercourse area can easily cause a slight break in the genital mucosa, and then the virus can take advantage of the situation and enter the bloodstream of uninfected people. It is worth mentioning that the risk of anal intercourse is greater than that of vaginal intercourse because the intestinal wall of the rectum is more easily broken than the vaginal wall. Blood transmission is the most direct route of infection. Importing blood contaminated with the virus, using blood-contaminated syringes, acupuncture needles, and tooth extraction tools that have not been strictly sterilized are all very dangerous. In addition, if you share an unsterilized syringe with an HIV-infected person, you can also be infected by the virus left in the needle. If a mother is infected with HIV, she is likely to infect her child during pregnancy, childbirth, or through breastfeeding.