Aiming at the economic benefits of fishing,a predator-prey model with periodic coefficients is discussed. The dynamic characteristics of the model and the optimal harvesting strategy of two species under capture conditions are studied. In order to understand the dynamic characteristics of the stability of the model system,the existence and uniqueness of periodic solutions of the model system are obtained by using the upper and lower solutions theory of differential equations. The sufficient condition guarantees the stability of the periodic solution. From the persistence and permanence of the model,the conditions affecting the permanence of the model system are obtained. Finally,the optimal harvesting strategy of the model under capture conditions is obtained by using the maximum principle. The purpose is to maximize the economic benefits of fisheries,ensure the economic benefits of society and protect the ecological environment while maintaining the stability of the ecosystem.