In this paper, a dynamic model of new coronary infectious disease is established by using differential equations. The existence and stability of equilibria are proved. Based on the epidemic data published by the Health Commission of Heilongjiang Province, the model parameters are estimated by the least-squares algorithm. In addition, the estimated parameters are substituted into the model for fitting comparison. The development of the third COVID-19 epidemic in Heilongjiang province is predicted. The effective strategies for prevention and control of the recurrence of COVID-19 are proposed.