In recent years, there has been a growing interest in switched reluctance motor when it is widely used in the field of electric vehicles for its simple structure, low cost, high reliability, wide speed range, high response speed, high operating efficiency and strong renewable braking ability. The performance and structure of the power converter will directly affect the efficiency, cost and reliability of SRM, so the reasonable design of SRM power converter is the key to increase the cost performance of the whole SRM speed control system. Based on the principle and advantages of SRM, an improved asymmetrical half-bridge structure power converter with soft-switching is proposed for SRD in the paper. The DC / DC switching mode power supply for switched reluctance motor drive system is also successfully designed based on LT1247 integrated chip. Experiment results show that the new type of power converter and the DC / DC switching mode power supply can work better on electric vehicles.