In order to improve the dynamic and robust performance of the medium frequency power supply, the robust controller is applied to the medium frequency power supply control. Based on the mathematical model of the control object, at the same time, the load and the filter inductance parameters are taken as uncertain factors, a robust controller is designed based on the μ analysis and synthesis method. Simulation and experimental results show that the dynamic response speed is improved by one times than that of the intermediate medium power supply controlled with double loop quasi PR controller, and the fluctuation of voltage in the dynamic process is reduced by nearly 40%. The medium frequency power supply controlled with robust controller not only can achieve the tracking and asymptotic stability, but also has good robust performance and strong anti-interference to the load disturbance.