Energy storage has the potential to take part in the frequency regulation in the power grid because of its flexible control function, and there are more and more studies focusing on it. The frequency response of energy storage is continuous and instantaneous, which can increase the stability and security of power grid and can be used to the second and third defense lines. However, the current research on energy storage participating in frequency control is still limited: most studies mainly focus on energy storage participating in primary and secondary frequency regulation, and few studies on emergency control involve overfrequency generator tripping. Therefore, based on model predictive control and moving horizon estimation, a control strategy of energy storage participating in frequency regulation is proposed. This paper considers the constraints of energy storage, energy storage is played as much as possible to reduce the quantity of tripping generators in the frequency regulation. The real-time frequency deviation of power system can be predicted by the moving horizon estimation in order to calculate the optimal energy output of energy storage system. Finally, the validity of the strategy used in this paper and its superiority over the conventional strategy are proved by some case studies.