The new coronavirus (COVID-19) pneumonia is highly infectious, and its symptoms are hidden, which is seriously damaging to social public security. As the fourth largest epidemic area in China, it is a good case for studying the spatial diffusion of epidemics to explore the epidemiological characteristics and spatial diffusion law of COVID-19. Based on the data of pneumonia cases diagnosed with novel coronavirus infection in Zhejiang Province from January 21 to February 29, 2020, SPSS24.0 was used for data mining and ArcGIS10.2 for spatial analysis The main results are: 1) The temporal variation of the number of new cases in Zhejiang Province has the characteristics of randomness, which conforms to the Poisson distribution function. The difference in infection rates between men and women was not significant. The typical symptoms of COVID-19 were fever, cough and pulmonary imaging lesions. 2) The infection rate showed significant spatial clustering, presenting as ‘One belt and four centers’. ‘One belt’ being the county level regional unit of the Taizhou-Wenzhou coastal railway belt, ‘four centers’ being Haishu district of Ningbo City (11.02/100 000), Xiuzhou district of Huzhou City (4.29/100 000), Shangcheng district of Hangzhou City (4.06/100 000), Jianggan district of Hangzhou City (4.80/100 000), and Tonglu County of Hangzhou City (5.78/100 000). On the whole, the areas with high infection rates are mainly concentrated in the areas with strong commercial exchanges, while the areas with low infection rates are concentrated in the regions with traditional industries and relatively less developed economies. 3) The cluster center of kernel density presents a North-South-North orientation transfer. The spatial evolution characteristics are four stages: ‘multi-core and multi-center’ ‘main nucleus fixation, polycentric evolution’, ‘single main nucleus, polycentric regression’ and ‘epidemic regression’.4) the diffusion rate in Zhejiang Province was first increased from January 29 to February 4, and then decreased from February 5 to February 29. According to the diffusion source, the Epidemic areas can be divided into: ‘no infection risk area’ ‘only endogenous infection with low risk area’ ‘mainly endogenous infection and high risk area’ ‘mainly exogenous infection with controlled high risk area’ ‘only exogenous infection and controllable risk area’. The internal logic of infectious disease deduction is the transmission from exogenous diffusion to endogenous contact. 5) From the evolution of the epidemic and the characteristics of the epidemic, the four-stage treatment strategy is proposed, such as: at the first stage, the fundamental measure for controlling infectious diseases is to cut the source of infection; at the second stage, it is important to promote group governance and prevention, and realize the common governance of the government, enterprises, communities, and individuals; at the third stage, the epidemic situation is classified and regulated to restore production and life; at the final stage, it is necessary to control the imported disease source powerfully. Four stage method is treating symptoms but not root causes. It is the fundamental solution to the public health problem to promote the construction of life circle and build a healthy city.
