Mother-to-child transmission is the main way of transmission of hepatitis B in China. A mother with hepatitis B can transmit it to her child, especially when the mother has a high level of hepatitis B virus replication in her body. Hepatitis B virus may be present in the blood, semen, saliva and breast milk of a person with hepatitis B. The higher the amount of virus, the more infectious it is. Hepatitis B can be transmitted through blood, body fluids, mother-to-child transmission, sexual contact, and contact with broken skin and mucous membranes. China is a country with a high prevalence of hepatitis B. Mother-to-child transmission is the main transmission route for hepatitis B in China, and it is estimated that 40% to 50% of infected people are infected by mother-to-child transmission. 60% of children born to hepatitis B mothers can be infected with the hepatitis B virus within two years, while 95% of children born to e antigen-positive mothers are surface antigen-positive within one year. After the child is born, the hepatitis B mother can also transmit hepatitis B to the child through close contact in daily life such as breastfeeding, kissing and feeding, especially when the mother’s nipples are cracked and the baby has ulcers in the mouth, which is more likely to cause transmission of hepatitis B between mother and child. Moreover, about 90% of hepatitis B infections in infants and children will become chronic and become slow hepatitis B patients, and some slow hepatitis B patients will develop cirrhosis and liver cancer, which is very dangerous. Therefore, we recommend pregnant women with serum hepatitis B virus >2×106copeis/ml to start antiviral treatment in the 24th-28th weeks of pregnancy, and their babies should be injected with hepatitis B immunoglobulin and hepatitis B vaccine as early as possible within 24h after birth (preferably within 12h after birth) to prevent and block hepatitis B virus from infecting their babies. Therefore, mother-to-child transmission is the most important way of hepatitis B transmission in China, and the mother can inherit hepatitis B to her child, especially if the mother has hepatitis B virus >2×106copeis/ml in her serum, she should seek medical attention promptly.