In order to mitigate the impact of wind power fluctuation on the power grid, a model predictive control algorithm is proposed to analyze the optimal allocation of energy storage system with different fluctuation rate of wind power. Firstly, based on the model predictive control (MPC) algorithm, the control strategy of using energy storage to smooth the wind power fluctuation is studied, and an optimal configuration model is established. Secondly，the concepts of positive and negative fluctuation rate and cumulative fluctuation rate of wind power are proposed，and the power and capacity allocation strategies of energy storage system under three typical fluctuation rates are analyzed in steps. Finally, three typical scenarios, from the established standard sinusoidal wind power to the randomly selected wind power, are analyzed based on MATLAB software to verify the effectiveness of wind power fluctuation mitigation strategy based on model predictive control algorithm and the cumulative fluctuation rate difference as energy storage size evaluation index, which provides a reference for the friendly grid connection of renewable energy and energy storage optimal configuration.