In this paper, a modified laser-trigged vacuum switch(LTVS) is developed to optimize the triggered vacuum switch (TVS) and complies with the requirements of pulsed power technology. The comparison between a flat-electrode type switch and a multi-electrode type switch is discussed founded on the simulation and experimental results. The results show that the delay time of the modified switch can reach as low as 17 ns and the operating voltage ranges from 60V to 20KV. Finally, laser energy influencing the trigger characteristics is analyzed built on the thermionic mechanism.