Abstract: The preliminary design of a new high-power low-pressure plasma-cathode e-gun is presented. Based on the hollow cathode effect and low-pressure glow discharge empirical formulas, the hollow cathode, the accelerating gap, and the working gas pressure region are given. The general experimental device of the low-pressure plasma cathode electron-gun generating high current density e-beam source is shown. Experiments has been done in continuous filled-in gases and gases-puff condition, and the discharging current of 150~200 A, the width of 60 μs and the collector current of 30~80 A, the width of 60 μs are obtaind. The results show that the new plasma cathode e-gun can take the place of material cathode e-gun, especially in plasma filled microwave tubes.