Abstract: The hollow cathode pseudospark switch has excellent operating characteristics of high holdoff voltage, high peak current, and rapid current rise. In this paper a computer simulation of its initial discharge coursed is presented. The simulation consists of a 5/2 – dimensional time – dependent fluid model for electron and ion transport using the local field approximation. The result shows that the hollow cathode plays a very important role during the discharge. Also we give the calculation results under different initial triggering charged – particle densities, different gap distances and different cathode hole diameters.