Abstract: Based on the need of high power repetitive pulse power source, the repetitive frequency characteristics of high power pulse charging power supply are studied in this paper. The constant current charging technology based on the full bridge series resonant charging principle is analyzed. According to the work requirement of high power Marx type pulse power source, the key parameters of the series resonant charging are calculated. The compact high power pulse charging power supply, with the maximum output voltage ±50 kV, the charging current 2.5 A and the repetition frequency 1-50 Hz, can run stably for a long time under the condition of repetition frequency. The charging power supply has the advantages of small volume, light weight, strong anti-interference ability and strong resistance to short circuit, and has been applied to the research of high power repetitive pulse power source technology, in which it has achieved 100 000 times repetition-frequency operation without fault.