Hepatitis B generally refers to chronic hepatitis B, which is caused by infection of hepatitis B virus, and is related to blood and body fluid transmission and mother-to-child transmission. 1. Blood and body fluid transmission: Hepatitis B patients and HBV carriers are the main source of infection, and they are easily infected if they share syringes and needles, or if their mucous membranes come into direct contact with patients’ blood. Usually related to surgery, hemodialysis, organ transplantation and other medical operations, as well as sharing toothbrushes, razors and other items, but also through sexual contact, through saliva, semen, vaginal secretions and other bodily fluids to spread. 2. Mother-to-child transmission: it mainly includes intrauterine infection, perinatal transmission and post-delivery transmission. Intrauterine infection is mainly through the placenta; perinatal transmission is the infection that occurs when the baby is exposed to the mother’s blood, amniotic fluid or vaginal secretions by broken skin or mucous membranes; post-delivery transmission is when the mother breastfeeds the baby. In conclusion, when tested for hepatitis B, you need to actively cooperate with your doctor for standardized treatment. Those who have close contact with hepatitis B patients and are at risk of infection should be vaccinated against hepatitis B in a timely manner.