Solid state pulse switch modules are developed for high power modulator. Internal semiconductor physical process and equivalent circuit of insulated gate bipolar transistor(IGBT) are analyzed. Based on power electronics simulation software Saber and its modeling tool, physical model of discrete chip IGBT IXDH 20N120 is implemented. With this model, output performance of pulse switch modules and solid state modulator with different circuit parameters and topologies is simulated. It turns out that dynamic voltage balance network could effectively protect switch modules and reduce IGBT switch’s power loss. On the other hand, random changes of trigger signal transmission delay time and stray capacitor in the circuit worsen the modulator’s output pulse quality and efficiency. The modulator’s