Abstract: Epidemic diagnosis time can scientifically evaluate and comprehensively reflect the emergency level and physical therapy capacity of a national or local health department. Based on the diagnosis and treatment time records of more than 70 000 diagnosed or suspected cases of coronavirus disease 2019(COVID-19) provided by the Chinese Center for Disease Control and Prevention (CDC), this paper uses regional statistics, spatial mapping, trend simulation, and significance testing to analyze the temporal and spatial distribution, spatial differentiation and dynamic process of the early diagnosis time of COVID-19 in Chinese mainland. Results show that:(1) The average epidemic diagnosis time for COVID-19 outbreak from early onset to diagnosis is 7.35 days. Among them, Hubei Province is 7.99 days, and the average diagnosis time in other provinces is 5.68 days. The average time from suspect to diagnosis is 3.86 days, 4.08 days in Hubei, and 2.91 days in other provinces. Although the epidemic diagnosis time in Hubei Province is slightly higher than the average, the difference in spatial differentiation is not particularly noticeable. The average dispersion of diagnosis time is only 0.58 days. (2) The dynamic process of COVID-19 diagnosis time shows a significant decrease trend(Slope=-0.78, P < 0.01, two-tailed), and the diagnosis time quickly drops to 1 day within 2 months of the early outbreak. This greatly improves the efficacy of epidemiological diagnosis. (3) Pearson correlation analysis between epidemic diagnosis time and healing period shows significantly related (P < 0.01, two-tailed). Early diagnosis and early treatment can reduce the time for patients to heal. All patients are treated in time to effectively improve the cure rate. The above research results indicate that:Chinese government has steadily promoted the overall prevention and control of the epidemic, and achieved remarkable results. Efficient diagnosis reduces the natural exposure time of the virus, reduces the time to cure and the probability of potential cross-infection. It has laid a solid foundation for the prevention and control of the epidemic in China in a short period of time and the nationwide resumption of work and production.