With increasing penetration of wind power in China,the wind power variation can degrade the grid operation safety,dispatching ability restricts the wind power grid,causing wind curtailment in large area and even endangering safety of power grid.Allocating energy storage system can decrease wind curtailment and improve the economic benefits of wind farm. Firstly, this paper analyzed wind power fluctuation and power curtailment characteristics data and determined fluctuating component and principle of scene division by the statistical result. Meanwhile,considering the power fluctuations smoothing, power benefit by reduced wind curtailment,investment cost.Finally,this paper solved the model by using optimization algorithm to determine the capacity of the hybrid energy storage system.Case study results show that wind power fluctuation under 10 minutes will be limited to 20% of installed capacity and reduced wind curtailment as well. It also verified the economical efficiency and feasibility of the proposed method.