Abstract: When an energy storage system is controlled based on state of charge (SOC) to participate in primary frequency control, the performance of the energy storage system is limited due to the relatively single output constraint condition of the energy storage system. To solve this problem, a primary frequency control strategy based on multiple constraints of energy storage system is proposed. Firstly, the double-layer fuzzy control method is used, so that the multi-time scale frequency modulation dead zone of the energy storage system is determined as the first constraint to avoid the frequent operation of thermal power units and energy storage batteries. Secondly, SOC is taken as the second constraint condition, and the constraint factor is taken as the third constraint condition. A comprehensive control model of inertia and sag is built based on the logistic curve to constrain the output of the energy storage system. Finally, the high precision SOC is used to construct a fast balancing function to shorten the SOC balancing time. Simulation models are built to verify the effectiveness of the proposed control strategy under the conditions of step load disturbance and continuous load disturbance, respectively.