Abstract: In order to study the factors affecting the ionization of Penning ion source inside a high-current pulsed electron beam, a two-dimensional axisymmetric model was established based on the finite element simulation software to simulate the internal magnetic field and electron distribution, and then the effects of anode voltage, magnetic field strength and air pressure on the argon Penning discharge and radial distribution were simulated and studied. The ionization condition and the variation of electron distribution with these three factors are analyzed. The simulation results show that the effect of the electric field on ionization is positively correlated with that of a low electric field at high pressure. When the electric field is large, the influence of the electric field on the ionization degree is negatively correlated. The increase in magnetic field will increase the ionization rate, and the increase in magnetic field intensity will not affect the ionization rate after the increase to 1 T. The influence of the electromagnetic field on the radial distribution of electrons is not obvious. Pressure is positively correlated with ionization. In addition, the smaller the pressure, the more uniform the radial distribution of electrons.