Dried bloodstains that contain active hepatitis B virus have a certain risk of transmission if they come into contact with broken human skin and mucous membranes after getting wet and the contaminated person does not have surface antibodies to the hepatitis B virus. Hepatitis B virus has a high ability to survive in the outside world. The virus is resistant to heat, low temperature, dryness, ultraviolet light and general concentration of disinfectant, and can survive for 7 days at 37℃. Therefore, if the blood comes from patients with acute or chronic hepatitis B and virus carriers, even if the dried blood stains are wet, they are still infectious. Hepatitis B virus can be transmitted through blood, when the blood containing the virus comes into contact with broken skin or mucous membranes, the virus will enter the human body to a certain extent and cause infection, especially for patients with poor immunity or people who are negative for surface antibody against hepatitis B virus, the risk is higher. Therefore, the blood of high-risk people should not be taken lightly even if it is dried. Since the virus is sensitive to 0.2% Neosporin and 0.5% peroxyacetic acid, blood can be disposed of with disinfectants to reduce the risk of infection. Daily care should be taken to avoid ear piercing and tattooing in unregulated street stores to prevent increasing the risk of hepatitis B virus infection.