Clinically infectable human novel coronavirus pneumonia can be classified as mild, common, severe, and critical according to the degree of morbidity after infection. In addition, there is also an asymptomatic infected person, that is, a person infected with novel coronavirus without any clinical symptoms in the body, only positive by viral nucleic acid test. As the disease progresses, asymptomatic infections can develop into mild, common, or even heavy cases. The mild form generally refers to a mild onset of symptoms with no imaging evidence of pneumonia. The common type has typical symptoms of neoconiosis, including fever, cough, sputum, sore throat, peripheral weakness, nasal congestion, runny nose, and in some cases, abnormal smell and taste as the first symptoms, and diarrhea. Severe and critical cases are usually more severe, with increased oxygen saturation index and respiratory rate, and the mortality rate is higher in severe and critical cases.