Objective To investigate the positive time length of nucleic acid detection in 22 confirmed cases of coronavirus disease (COVID-19) in Yangzhou and analyze the influencing factors, and to provide evidence for the prevention and control of the disease. Method A total of 22 confirmed cases were followed up for five weeks. Throat swabs were collected for nucleic acid detection. The relevant data were collected and statistical analysis was conducted on the basis of survival analysis. Results The positive rate of throat swabs was 100%, 100% and 66.67% at 1-2d, 3-4d and 5-7d, respectively, after the onset of COVID-19. The average positive time of all confirmed cases was 16.32 days, including 18.50 days for common type and 13.70 days for light type. The difference was statistically significant (χ²=4.36, P=0.037). Multivariate Cox regression analysis showed that case type (or=0.19, 95%CI:0.06-0.61) and onset visit time (or=0.70,95%CI:0.55-0.88) had an impact on the positive time length of nucleic acid detection. Conclusion The positive rate of respiratory samples is high within one week after the onset of the confirmed cases, and the positive time length of light type cases was shorter than that of common types. The positive time length of nucleic acid detection may be shortened after timely treatment with drugs.