Pseudospark (PS) discharge is promising source for high brightness and high intensity electron beam pulses. In the present paper, an effort has been made to analyse the temporal behaviour of discharge current, applied voltage, plasma density in the PS discharge based PCE-Gun at different hollow cathode aperture sizes using 3-D particle-in-cell (PIC) simulation code "VORPAL". The peak discharge current in the PS discharge is a function of hollow cathode dimensions. The plasma generation process by self ionization discharge is examined at different operating conditions. Argon is taken as the background neutral gas. It has been observed that the decrease in the aperture size from 8 mm to 3 mm increases the discharge current, the electron confinement time and the plasma density. © 2015, National Institute of Science Communication and Information Resources (NISCAIR). All rights reserved.