Monkeypox virus belongs to the class of poxviruses, and smallpox virus belongs to the genus Orthopoxvirus, which is a kind of DNA virus. 1. Monkeypox pathogen is a double-stranded DNA (deoxyribonucleic acid) virus, which is similar to smallpox virus and belongs to the genus Orthopoxvirus, but the infectiousness of monkeypox virus is far less than that of smallpox virus, and the structure of the RNA virus is more stable compared to the probability of mutation is relatively low. 2. Monkeypox virus is long oval or rectangular under electron microscope, it can resist ether, but it can be easily inactivated by methanol, formalin or chloroform, and it can also be inactivated by heating at 56℃ for 30 minutes. 3. The clinical manifestations of monkeypox and smallpox are similar, mainly characterized by high fever, local lymph node enlargement and blisters and pustules all over the body, accompanied by hemorrhagic tendency.