A novel inductive energy storage pulsed power source design has been presented, with two energy storage coils separated by a water transmission line. Considering the transmission line as a capacitor, the novel principle circuit was simplified and the discharging formula of the inductor was derived. The formula shows that, the novel technology changes the traditional pure exponentially-decayed discharging waveform into a combination of an exponentially-decayed discharging waveform and a sinusoidally-damped oscillation discharging waveform, which can improve the output waveform and increase the energy conversion efficiency. Based on this theory, experiments have been carried out and an electron beam with a voltage of 300 kV and a current of 20 kA was generated. Several hundreds megawatt micr