Abstract: The flash X-ray generator with an industrial X-ray diode would be widely applied in research and industrial detection, which is capable of generating intense x-ray under high repetitive frame. An industrial X-ray diode was driven by the pulsed power supply under 100 Hz to 1 kHz, whose copper cathode was heated to analyze how the surface adsorption affects the electrons emission process. Plasma diffuse processes were investigated simply based on voltage duration and impedance model. The study shows that explosive emission electrons come from gas desorption on copper cathode surface, and the key factor affecting repetitive rate is not diode recovery. Gas absorption velocity between shots is under no more than 1 kHz, so it is a groundwork to develop a novel cathode capable of supplying enough electron beam with high repetitive rate.