Abstract: The restrike phenomenon during the opening of vacuum circuit breaker will cause overvoltage, resulting in the deterioration of the insulation of high voltage equipment. To solve this problem, an experimental study on the restrike characteristics of vacuum circuit breaker during the breaking process is carried out, a voltage withstand test platform for 40.5 kV vacuum circuit breaker is built, and the effects of contact spacing, loop current and inrush current during the closing process on the restrike times, the steepness and duration of the breakdown voltage wave front are obtained. The test results show that the number of re-breakdown decreases and the duration of breakdown arc increases with the increase of contact spacing of vacuum circuit breaker. With the increase of circuit current of the test system, the number of restrike, the steepness of the breakdown voltage and the duration of the restrike arc increase during the breaking process of the vacuum circuit breaker. With the increase of inrush current amplitude during vacuum circuit breaker closing process, the number of re-breakdown and the duration of restrike arc during vacuum circuit breaker breaking process increase. It provides theoretical basis and data support for the preventive test and the optimization of voltage test method of 40.5 kV vacuum circuit breaker.