In this thesis, the design of a Switching Power Supply for switched-reluctance motor drive system power factor correction is presented. Switching power technology for the power supply is now widely used, which has the main advantages of high efficiency and small size. However, the traditional type of Switching Power Supply will reduce the impact on electricity usage and quality, and produce electricity pollution and waste, for example low power factor, and high harmonic distortion. In order to improve the power factor, this paper used the traditional method of multiplier power factor correction circuit, and the use of state-space averaging method to analysis Buck Derived Converters to implement the Switching ¡@ Reluctance Motor Drive circuit design; In addition, this thesis used the Average Current Control method to cause the inductor current to follow a sinusoidal signal, achieving the purpose of¡@power factor correction.The design of Buck Converters is based on switching theory. With this method, the electricity pollution problems introduced by switching reluctance motor drives is solved by the Averagingmethod derived form the converters. The mathematical Buck Converter model is brought into a block diagram, based on the design of Buck¡@Converters, and then simulated with PsPICE software. Finally the design of the output voltage control, compensation and current control loop is performed.