Objective In the early operation stage of Jinan Metro Line 3, multiple sporadic high-speed circuit breaker closing failures are reported. To improve the reliability of train operation, it is necessary to optimize the high-speed circuit breaker control circuit in the traction system. Method According to the relevant closing command and the component status when a closure failure of the high-speed circuit breaker on Line 3 train occurs, and in accordance with the control logic principle of the high-speed breaker, the causes of the occasional closure failure are analyzed and the optimization measures are put forward. Result & Conclusion The causes of the occasional closure failure are that in the process of closure control of high-speed circuit breaker, the induced electromotive force generated at both ends of the high-speed circuit breaker coil makes the closing power insufficient, resulting in the failure closure of the breaker. The improvement measure is to connect freewheel diodes at both ends of the h