Abstract: An improved sliding mode control method based on the approach law is proposed in this paper,which improves the inverter side design of the grid simulator.The appropriate power grid simulator topology is selected,and the mathematical model of the three-phase full-bridge inverter is established in this research.The original control method is improved by the double-power sliding mode approaching law.The control block diagram of the system was designed in Simulink and the simulation results were compared.Based on the PHIL real-time simulation technology,the grid simulator experimental platform was built and the experiment was carried out.The results show that the improved sliding mode control can effectively reduce the chattering phenomenon and improve the stability of the system.