For the vacuum circuit breaker (VCB) breaking frequently in high-speed railway, contacts were repeatedly corroded, and tips, coarsenesses and reduction of vacuum degree of diffusing metal vapor were caused by arc during breaking. The experimental program was proposed of characterizing VCB electric life by measuring contact resistance of normal current under different breaking number. Meanwhile, the characteristics of withstanding impulse voltage and frequency voltage under different breaking number were obtained. Studies have shown that the contact resistance was initially increasing with the increase of breaking number, and after that, contact resistance was unchanged; in the initial testing period, the transient recovery voltage could not cause reignition of arc, but multiple reignitions of arc would happen possibly with working in a long term, although the gas of interrupter could not be breakdown by workingfrequency voltage.