Abstract: A high power high voltage constant current capacitor charging power supply is designed and manufactured. It adopts full-bridge topology with series resonant constant current charging technology and the output voltage is adjustable from 0 to 30 kV, the average power can reach 5 kW at the most. The operating process of the circuit is analyzed briefly. The parameters of the power supply are calculated and a designed example is presented. The simulation and experiments are given and the experimental results are in accordance with the calculation request. In experiment, an 18 F capacitor is charged to 30 kV at 0.1 Hz repetition rate by the power supply, the average power is about 1.35 kW. Now the power supply is experimentally investigated for a capacitor charging and it can work steadily.