Abstract: The paper analyzed problems of original design scheme of high voltage capacitor cabinet of Baimahe air shaft substation in Nantun Coal Mine, and gave its improvement design: selecting vacuum circuit breaker for capacitive load; adding discharge coil and connecting the coil with a capacitor in parallel directly to form a complete discharge circuit; adding grounding switch which has both mechanical latch and electrical interlock for easy operation and high security. The practical application shows that the improved high-voltage capacitor cabinet has more functions and high security and reliability.