Smallpox is a virulent infectious disease induced by smallpox virus infection, which can be transmitted by droplet inhalation or direct contact, as well as by some indirect contact methods. Smallpox virus is a typical virulent virus that is highly contagious and spreads rapidly. It can be transmitted through close contact, indirect contact, and also through aerosolized airborne transmission. Smallpox virus invades the skin tissue cells through contact, it will induce epidermal cell proliferation, localized swelling, leading to cell degeneration, necrosis induced fluid exudation, the formation of herpes, and at the same time, a large number of replication of the virus into the bloodstream and subsequently can be involved in the respiratory tract, the digestive tract, the urinary tract, vagina and other mucous membranes, ultimately leading to the lowering of the body’s resistance and the failure of the organism organs, triggered by the death. However, starting from the late 19th century, smallpox vaccine began to spread globally, and as early as 1979, the World Health Organization declared that smallpox had been completely eradicated from the human race.