The smallpox vaccine is usually given at the time of vaccination at the age of 1 to 2 years. However, smallpox virus has now been completely eradicated. Smallpox is a virulent infectious disease caused by the smallpox virus, which mainly invades the human body through the mucous membranes of the respiratory tract and is transmitted through droplet inhalation or direct contact. Smallpox is highly contagious and the general population is susceptible, especially those who have not been vaccinated against smallpox and those who have never had smallpox. Smallpox vaccination is one of the ways to prevent viral infection. Currently, the commonly used smallpox vaccines are liquid cowpox vaccine and freeze-dried cowpox vaccine. Smallpox vaccine is taken from the live virus of cowpox. By inoculating 1~2 children with smallpox vaccine, the human body can produce the virus immune function, thus playing the role of immunization against smallpox virus and avoiding smallpox. Smallpox is prevention-oriented. In addition to smallpox vaccination, smallpox can also be prevented by wearing masks during smallpox epidemics. Smallpox is now an eradicated infectious disease with the widespread use of smallpox vaccination.