In order to improve the electricity exchange efficiency of urban pure electric bus and reduce the construction and operation costs of charging stations, this paper studied the optimization of urban battery exchange pure electric bus charging station siting and capacity selection. Firstly, considering the operation guarantee capacity of pure electric bus exchange stations, the study established a model of the number of exchange facilities and battery reserve capacity and obtained the number of exchange stations and optimal battery configuration. Then, based on the pure electric public exchange demand, the charging station operation conditions were modeled by using queuing theory, and penalty factors were set to ensure the service quality of charging stations. A site selection and capacity model with service radius, service intensity and supply and demand balance as constraints and minimum annual total cost as the object was established, and GA, PSO and PSO-GA algorithms were applied to solve it. Finally, a sensitivity analysis of the siting and capacity model was performed to obtain the effects of parameters such as charging rate and rated driving range on the siting results. The results of the case application show that the PSO-GA algorithm is better than the GA and PSO algorithms in terms of objective function and convergence speed, and the optimal number of charging stations is 30, the number of charging piles is 943, and the lowest total cost is 12 151 429 000 RMB. The rated driving range of pure electric buses is negatively correlated with the number of stations, transportation cost and construction cost; the charging rate is negatively correlated with the number of stations and construction cost and positively correlated with transportation cost, and increasing the charging rate will accelerate battery aging and reduce battery life. The research results can provide theoretical basis for the reasonable planning and operation of urban pure electric bus charging stations.