The diagnosis of novel coronavirus relies on a comprehensive analysis of epidemiologic history, clinical manifestations, and pathogenetic or serologic evidence to make the diagnosis. Among them, a positive nucleic acid test for the new coronavirus is the primary criterion for confirming the diagnosis. 1. Epidemiologic history: history of travel to an infected area 14 days before the onset of the disease; history of contact with a person infected with the new coronavirus 14 days before the onset of the disease; contact with a patient with fever or respiratory symptoms in the community that reported its own case 14 days before the onset of the disease; and entry and exit from a place of aggregation of the onset of the disease 14 days before the onset of the disease. 2. Clinical manifestations: clinical symptoms related to new coronavirus pneumonia such as fever and/or respiratory symptoms; imaging features of the aforementioned new coronavirus pneumonia; normal or reduced blood leukocytes and normal or reduced lymphocyte counts in the early stage of the disease. 3. Pathogenetic or serologic evidence: positive nucleic acid test for novel coronavirus; positive antibody specific to novel coronavirus in unvaccinated persons. The new coronavirus is highly infectious and mutates rapidly. Those with epidemiologic history should be reported promptly; when uncomfortable symptoms occur, nucleic acid testing should be improved to diagnose or rule out the diagnosis. Protection should be taken in daily life to avoid infection with new coronavirus or causing the spread of new coronavirus. Tips] The “new coronavirus pneumonia, new coronavirus pneumonia” mentioned in this article has been renamed to “new coronavirus infection” on December 26, 2022, as announced by the National Health Commission.