Measuring age heterogeneity and the role of vaccines in the epidemic, an age-structured SVEIHR model is developed to simulate the propagation of the third outbreak of COVID-19 in Liaoning Province. Based on the actual data, parameters are obtained by the MCMC method and used in numerical analysis and the calculation of the basic reproduction number for different contact patterns and vaccine efficacy. The appropriate method of epidemic management obtained in this paper is to conduct self-quarantine first, and then resume work under the management policy, which can productively halt the epidemic. Besides, it is found that vaccination can effectively alleviate the epidemic situation. Specifically, the more effective the vaccine is, the fewer people will become infected.