Aiming at the difficulty of the peak shaving in power system caused by the uncertainty of wind power grid connection and improved the comprehensive utilization rate of new energy sources, an optimal strategy of peak-shaving for energy storage based on the in-depth analysis of the energy peak shaving principle was proposed. Firstly, introduced the influence of wind power reverse peak shaving properties, and determined the minimum peak clipping power and maximum valley filling power, then added the peak shaving reliability constraint based on the system power balance constraint, energy storage system constraint and power side constraint to establish the system optimization model aiming at minimizing load variance. Finally, the evaluation index of peak shaving reliability was constructed. Based on the load data of a certain power grid within a certain period of time, the calculation example was analyzed and compared with the constant power strategy. The simulation results verify that the method in this paper has a better peak shaving effect.