The source of the novel coronavirus is not particularly clear at this point in time, and may be related to animals and contaminated environments, but it is not absolute. At first, animal-to-human transmission was considered, followed by adaptation of the virus to the host mutation, but now human-to-human transmission is occurring and widespread transmission has occurred. New coronavirus pneumonia has in many ways the common features of coronavirus at the time of its emergence, but also has its own characteristics. The new coronavirus is 85% homologous with SARS, and the source of infection is seen so far, mainly in patients with pneumonia infected with the new coronavirus can be transmitted by proximity droplet transmission, contact transmission and aerosol transmission. Patients with novel coronavirus are already infectious when they have no symptoms during the incubation period.