Chronic hepatitis B (HBV) seriously endangers human health, and the rate of HBsAg positivity in the general population in China is as high as 9.18%. The chronicity rate of hepatitis B virus (HBV) infection depends on the age of infection, the younger the age, the greater the chronicity rate. 70%-90% of perinatal infections can develop into chronic infections, so blocking mother-to-child transmission is the key to preventing chronic HBV infection. How can mother-to-child transmission be interrupted? Vaccination against hepatitis B is the most effective measure to prevent HBV infection. The active ingredient of the hepatitis B vaccine is HBsAg, which induces the body to actively produce anti-HBs and works. The hepatitis B vaccine is usually given in 3 doses, according to the 0, 1, and 6 month schedule, i.e. after the first dose, the second and third doses are given 1 month and 6 months apart, respectively. In principle, the first dose of hepatitis B vaccine for newborns should be given within 24 hours after birth, the earlier the better. For newborns born at full term to HBsAg-positive mothers, hepatitis B immune globulin (HBIG) and hepatitis B vaccine (3 doses at 0, 1 and 6 months) must be administered promptly after birth. The active ingredient is anti-HBs, which starts to work 15-30 min after intramuscular injection, and the protective anti-HBs can be maintained for at least 42-63 days, when the body has actively produced anti-HBs, so there is no need for the second injection of HBIG. if the HBsAg result of the pregnant woman is unknown, it is better to give HBIG to the newborn if possible. if the mother is HBsAg negative, the newborn will be vaccinated with HBIG. Children who were not vaccinated against hepatitis B during the neonatal period should be given a catch-up vaccination. Hepatitis B vaccination for preterm infants is different from that for term infants. Premature infants with HBsAg-negative pregnancies, if their vital signs are stable and their birth weight is ≥2000g, can be vaccinated according to the 3-dose regimen at 0, 1 and 6 months, preferably with a booster dose at 1-2 years of age; if the vital signs of preterm infants are unstable, they should first be treated for related diseases and then receive a booster dose when their condition is stable. If the infant’s vital signs are unstable, he or she should first be treated for the disease in question and then be vaccinated according to the above protocol after the condition is stabilized. If the preterm infant is <2000g, the first injection should be given after the weight reaches 2000g (if the weight does not reach 2000g before discharge, the first injection should be given before discharge); after 1-2 months, the 3-injection program should be repeated at 0, 1 and 6 months. A second injection is required after 3-4 weeks. If the vital signs are stable, there is no need to consider weight, and the 1st vaccination should be given as soon as possible; if the vital signs are unstable, the 1st vaccination should be given as soon as possible after stabilization; after 1-2 months or after the weight reaches 2000g, the vaccination will be re-administered according to the 3-dose protocol at 0, 1 and 6 months. After the first vaccination, most newborns are still negative for anti-HBs or below the lower limit of detection, so parents should not be too nervous; anti-HBs will turn positive only about 1 week after the second vaccination, which means that the body becomes immune to hepatitis B virus; the third vaccination can significantly increase the level of anti-HBs and prolong the protection period. The anti-HBs conversion rate of newborns after full vaccination is as high as 95%-100%, and the protection period can be more than 22 years. Therefore, there is no need for booster vaccination for non-high-risk groups.