Pox generally refers to smallpox is a virulent infectious disease caused by the smallpox virus that infects people and provides lifelong immunity after healing. Smallpox is one of the oldest and highest mortality rate of infectious diseases, highly contagious, heavy disease, no smallpox or smallpox vaccination of people can be infected, mainly manifested as severe viraemia, high mortality rate after contracting the disease. The most basic and effective and the easiest way to prevent it is to receive cowpox. Smallpox clinical manifestations of heavy and light, heavy smallpox mortality rate of about 25.5%, 45% of cases appear fusion rash, 79% have bleeding phenomenon; light smallpox mortality rate of 0.1% to 1.0%. Smallpox virus is a kind of pox virus, people are infected with no special drugs can be treated, patients in the face after recovery will be left with pockmarks, “smallpox” thus named. Smallpox virus is brick-shaped, about 200 nm × 300 nm, resistant to dryness and low temperatures, in the scabs, dust and clothing, can survive for months to a year and a half. Smallpox virus invades the human body mainly through the mucous membrane of the respiratory tract and is transmitted through droplet inhalation or direct contact. Smallpox virus has two strains of viruses with different virulence, the virulent ones cause positive smallpox, i.e., typical smallpox; the weak ones cause light smallpox, i.e., smallpox-like.