Abstract: The output characteristics of an LCC resonant converter are studied for the pulsed plasma thruster (PPT) high-voltage storage capacitor charging technology. In order to meet the demands of the charging power supply with sufficient constant current output capability, the working principle of the LCC resonant converter in Discontinuous- Current-Mode (DCM) is analyzed, the working mode of the double-pulse output is emphatically analyzed, and the current output capability is maximized. In order to optimize the efficiency of the charging power supply, the soft switching implementation conditions of the converter are studied, especially the synchronous rectification technology is used in the energy feedback phase of the resonant tank to significantly reduce the power tube loss. In order to make the charging power supply have higher voltage accuracy, the soft switching hysteresis Burst technique is adopted in the constant voltage working phase. Finally, an experimental prototype with input voltage of 28 V, output voltage of 2 kV and maximum output power of 400 W is built. The effectiveness and feasibility of the proposed scheme are proved by experiments.