Abstract: The economic benefits and grid-side power quality of photovoltaic energy storage charging stations are directly affected by their operation efficiency. As insufficient consideration of operation efficiency during the capacity configuration can lead to unnecessary power losses, this paper proposes a multi-objective optimal configuration strategy for improving the operation efficiency of photovoltaic energy storage charging stations. By analyzing the impact of power losses of both the converter and the internal source line on the operation efficiency of the photovoltaic energy storage charging stations, this paper proposes evaluation indicators and calculation methods for the operation efficiency of charging stations, and discusses the impact of operation efficiency of photovoltaic energy storage charging stations on their capacity configuration. A multi-objective optimal capacity configuration strategy is established with the optimal economic benefits of charging stations, operation efficiency, and grid-side peak-valley power compensation capacity as the optimization objectives. Aiming at the characteristics of the optimization objectives, an improved non-dominated sorting genetic algorithm Ⅱ（NSGA-Ⅱ） is proposed to obtain the solution method for the optimization strategy. The effectiveness and superiority of the optimization strategy are verified through a case study on operation scenarios of a typical photovoltaic energy storage charging station in southwest China.