Negative for neo-coronary pneumonia means that the results show negative after nucleic acid testing, indicating a greater likelihood of no novel coronavirus infection. Currently, nucleic acid testing for neo-coronary pneumonia uses nasopharyngeal swabs, sputum and other lower respiratory secretions, and the accuracy rate can reach about 70%-90%. In order to prevent screening and diagnose Neoplastic pneumonia in the first place, nucleic acid testing is comprehensively performed in China after the Neoplastic pneumonia epidemic. It is a type of pathogenic test, which uses PCR to detect pathogenic nucleic acids in peripheral blood and tissue cells infected by pathogenic microorganisms. However, a negative nucleic acid test is not the only basis for confirming the diagnosis of neocoronavirus. For suspected cases or close contacts, it is possible that the novel coronavirus is in the latent phase and is prone to undetectable results. In addition, contamination of the sample taken or cross-infection can easily lead to false positives, so there are cases where multiple nucleic acid tests are given to the tested person, and the accuracy of new coronavirus testing can be improved by combining epidemiological history, imaging and pathogenic examinations.