With the development of power systems, the application of energy storage (ES) technology has become widespread. The bi-directional power regulation capability and fast response rate of ES system can effectively assist the cooperative operation of the grid and load. In this paper, a two-stage optimization model for ES locating and sizing considering economic benefits and charging and discharging strategies is established. The optimization objectives are improving the power quality of distribution network and maximizing the revenue of energy storage, respectively. The effectiveness of the above model is verified in a 33-node distribution network. The results show that a reasonable ES locating and sizing plan can improve the utilization rate of ES and the operation optimization of distribution network.