Hepatitis B, or viral hepatitis B, is a systemic infectious disease caused by the hepatitis B virus (HBV), with liver damage as the main cause. The infectious source of hepatitis B is mainly acute and chronic hepatitis B patients and virus carriers, and its transmission channels mainly include mother-to-child transmission, blood and body fluid transmission, and sexual transmission. 1, mother-to-child transmission: mainly includes intrauterine infection, perinatal transmission, post-delivery transmission. Intrauterine infection is mainly acquired through the placenta, which may be related to the slight abruption of the placenta during pregnancy. Perinatal transmission or the delivery process is the main mode of mother-to-child transmission, and infants are infected by contact with maternal blood, amniotic fluid or vaginal secretions due to broken skin or mucous membranes. Transmission after delivery is mainly due to close contact between mother and baby. 2, blood, body fluid transmission: blood hepatitis B virus (HBV) content is very high, a small amount of contaminated blood into the body can cause contamination, such as blood transfusions and blood products, injections, needle sticks, sharing razors and toothbrushes, hemodialysis, organ transplants, etc. can be transmitted. 3, sexual transmission: unprotected sexual contact with hepatitis B virus-positive people, especially those who have multiple sexual partners, their risk of infection with hepatitis B virus is increased. To sum up, there are three main ways of transmission of hepatitis B. Therefore, in order to prevent infection, it is advocated to take active or passive immunization, strengthen blood management, develop good personal hygiene habits, and clean oneself, etc.