Abstract: Detailed demand and optimization design of glow discharge cavity of pseudospark switch are presented. Based on the optimum structure, particle simulation and experimental investigation are given. The particle simulation shows that the designed discharge cavity is a glow discharge cavity and the set up time of glow discharge is approximately 18.5 ns. When glow discharge happens, the cathode voltage drop dominates the primary anode voltage drop. In the cathode voltage drop region, the ion density is larger than the electron density and the net charge density is a constant. The experiment indicates that, the glow discharge cavity works on the left region of Paschen curve; as the gas pressure increases, the discharge voltage drops. When the discharge current is more than 0.14 mA and less than