Abstract: This paper studies an optimization model that comprehensively considers the energy storage economy and the effect of peak shaving and valley filling, aiming at the configuration and output optimization problems of battery energy storage system when it is applied to grid side peak shaving and valley filling. This paper converts the investment cost, operation and maintenance cost, time-of-use electricity price benefit, and policy subsidies of the energy storage system into days as economic indicators. This paper takes the standard deviation of the load curve after the energy storage is connected as the evaluation standard for the effect of smoothing the load curve, and both of which are quantified as the characterization of the social benefits brought by the energy storage system. The multi-objective optimization problem is transformed into a single-objective optimization problem through linear weighting, then objective constraints are set, and the YALMIP toolkit is used to solve the problem in MATLAB. The optimal capacity, rated power and daily output of the energy storage system under different quantization coefficients and weighting coefficients are given through the calculation example. The ideal value of the power capacity ratio of the energy storage system is summarized, also the relationship between the optimization calculation results and the quantization coefficients and weighting coefficients in the calculation process of the optimization target is analyzed.