Hepatitis B is mainly transmitted through blood and body fluids, and the infection is transmitted through blood, medical, mother-to-child and sexual contact. Because it is not transmitted through the digestive tract, there is no significant relationship between eating with a person with hepatitis B. However, when there are ulcers in the mouth or broken mucous membranes, the chances of being infected increase. The use of hepatitis B vaccine is a fundamental measure to prevent hepatitis B. Newborns, health care workers, blood donors, and people with poor resistance are susceptible groups. The following groups of people should be vaccinated in time if they are not infected with hepatitis B: ① newborns born to HBsAg positive, especially HBeAg positive mothers; ② young children under 3 years old in areas with high prevalence of hepatitis B; ③ medical personnel and those who come into contact with blood; ④ patients who have received blood transfusion or blood products for many times; ⑤ family members of HBsAg positive people, especially spouses.