The fast control and protection switch in 10kv smart distribution network required stable trigger conduction at very low operating coefficients and high potential isolation, and the trigger route of plasma injection excited by pulse transformer could effectively meet the above requirements, but the trigger properties remained to be further studied. In this study, the influence of the intermediate energy storage capacitor and its value on the trigger propertied were focused on. The result showed that adopting the intermediate energy storage capacitor could generated the higher trigger voltage and trigger current, which meant that the trigger cavity was easier to conduct and could get more energy infusion, and trigger properties were enhanced; when adopting a larger intermediate energy storage capacitor, the trigger voltage and trigger current would be increased, and the threshold voltage would be lower. Based on the research, it could be known that adopting the intermediate energy storage capacitor with larger value at the secondary side of the pulse transformer could effectively enhance the trigger properties, which provided effective guidance and theory for its application in engineering.