Look at the history of epidemiology first. 1. The patient had a history of living and traveling in Wuhan, surrounding areas or areas with reported cases 14 days before onset. 2. The patient had a history of contact with COVID-19 patients 14 days before onset, and it was a confirmed case with positive nucleic acid test. 3. The patient had contact with patients with fever and respiratory symptoms in Wu Hanyou 14 days before onset. 4. It has the characteristics of clustering. Clinical manifestations: 1. The patient has symptoms such as fever, dry cough and fatigue. 2. The CT images of the lung can show the imaging features of COVID-19, and generally show the inflammatory shadow of the outer lung. 3. At the initial stage of the disease, the total number of routine white blood cells can be normal or reduced, and the lymphocyte count can be reduced. Any item 1 that conforms to the above epidemiology plus 2 clinical features or 3 clinical manifestations can be diagnosed as a suspected case. Confirmed cases need to be based on suspected cases, and patients can only be diagnosed if they have evidence of pathogenic examination, that is, the virus nucleic acid test is positive.