Abstract: SiC photoconducting switches (PCSS) have lots of advantages over conventional switches. By means of device simulator, a two dimension (2D) model of SiC PCSS was set up, and the effect of Vanadium doped concentration on the characteristics of SiC PCSS was explored in a capacitor discharging circuit. In the model, the concentrations of unintentional impurities nitrogen and boron were set to 1×1014 and 1×1011 cm-3 respectively, the wavelength and power of laser were set to 532 nm and 2400 W/cm2, and the initial voltage of the circuit was 1 000 V. When the vanadium doped concentration was 1×1012 cm-3, the circuit generated an unbroken current wave in the initial stage followed by a high leakage current. As soon as the switch was triggered by laser, a peak current of 88 A was formed. After laser triggering, a higher tail current was observed in the circuit. As the vanadium doped concentration was increased to 1×1014 cm-3, the leakage current and tail current both decreased, and the peak current was 8 A. Furthermore, when the vanadium doped concentration was 1×1017cm-3, the peak current reduced to 2.5 A.