Abstract: The epidemic in Xinfadi Market spreaded rapidly, which formed multiple epidemic spots in related market chains, restaurants, and communities, and resulted in multiple cluster outbreaks in households and workplaces. Huairou District was rated as a low-risk area, but there was still a risk of community-based transmission and household-based or cluster outbreaks due to imported cases from other districts. The five major risks of imported epidemic were as follows: first, business exchanges between the institutions within the local government's jurisdiction and population mobility factors such as commuting may pose an importing risk; second, people working in the public transport industry, scenic spots, and leisure places had a risk of being infected, and relevant environments may be polluted, thus posing a persistent importing risk; third, there was a possibility of transmission by imported cases who came from other districts and sought medical assistance in the medical institutions within Huairou District; fourth, medical staff working in fever clinics and laboratories and those supporting the prevention and control of epidemic in high-risk areas had a risk of exposure to polluted environments in the processes of receiving and treating patients, sampling, and testing samples; fifth, in the presence of the above-mentioned risks of infection, if infected persons were asymptomatic or failed to seek medical assistance in time, it would be impossible to achieve the aim of early detection, early treatment, and early isolation, thus resulting in community-based transmission. There are objective risks for imported epidemic. Close attention should be paid to the epidemic trend in Xinfadi Market; Meanwhile, comprehensive measures including enhancing classified management of various populations and graded management of public places, continuously carrying on patriotic public health campaign, and promoting healthy behavior should be adopted to reduce the risk of importing and transmitting epidemic.