The spread of the coronavirus disease 2019 (COVID-19) had resulted in 16 million infected individuals and 640000 deaths across the world as of July 27, 2020. Unfortunately, there is still no sign that the epidemic spread is slowing down. China, as the first country suffering from the widespread outbreak of the epidemic, has effectively contained the spread of the epidemic since March, 2020. Therefore, confirmed cases of COVID-19 from January 20 to March 18, 2020 were taken as the sample set to establish the susceptible-exposed-infected-recovered (SEIR) model. The model was used to analyze changes in the numbers of individuals becoming infected, exposed (latently infected), susceptible, and recovered in the experimental groups taking different non-pharmaceutical interventions (NPIs) and in the control group not taking any NPIs, so as to evaluate effects of different NPIs. By doing so, the research expects to provide references to other countries for formulating corresponding policies. The results show that type-A NPIs for reducing daily contacts with infected and exposed cases and type-B NPIs for decreasing the probability of post-exposure infections both can delay the timing of large-scale infections of the susceptible population, timing of the number of exposed individuals to peak, and timing of peaking of the number of infected cases, as well as decrease the peak number of exposed cases. Moreover, type-B NPIs have more significant effects on susceptible and exposed populations. Type-C NPIs for improving the recovery rate of patients are able to effectively reduce the peak number of patients, greatly decrease the slope of the curve for the number of infected cases, substantially improve the recovery rate, and lower the mortality rate; however, these NPIs do not greatly delay the timing of the number of infected cases to peak. In addition to these, considering effects of different NPIs on the susceptible and exposed populations and in delaying the timing for the number of infected cases to peak, it is found that the government’s organization of medical supply related companies to resume production exerts the best effect. As for reducing the epidemic number of patients in the core epidemic area (CEA, Hubei Province), delivery and putting-into-operation of Leishenshan hospital shows the best effect, followed by dispatching of medical staff to support Wuhan, delivery and putting-into-operation of Huoshenshan hospital, and construction of mobile cabin hospitals.