Opening switch technology is the key to inductive storage system. In this paper, the mechanism of conductor's electrically exploding is discussed. The experience formula is presented to determine the parameters of the electrically exploded conductor as an opening switch. And the configuration of such an opening switch is designed. Good results have been achieved in experiment. By the adjusting of conductor parameters, high-power pulse signals are generated with the duration of 280ns and the voltage gain of several tens. It is showed that this kind of opening switch can play an important role in high power microwave generation with such device as vircator used as the load.