In the design process of traditional lowvoltage electric vehicle switched reluctance motor (SRM) drive system, the first consideration was the volume and cost of the system. Generally, the isolation of the digital ground and the power ground was always neglected in the design of the MOSFET driving circuits and the phase current and bus voltage sampling circuits, which deteriorated the reliability greatly in the driving system. Based on the traditional drive circuit and resistance sampling circuit in nonisolated drive system, a highspeed optocoupler was proposed to isolate the PWM control signal from the MOSFET drive signal, and a linear optocoupler was used to isolate the phase current sampling signal and bus voltage sampling signal from the AD sampling signal of the controller. This method could achieve the isolation of digital ground and power ground without increasing too much the system size and cost, and thus further improve the reliability of lowvoltage electric vehicle SRM drive system. The proposed method had important application prospects.