This paper proposes a design method for a high-power pulsed power supply for YAG laser systems, which is capable of realizing high-energy repetitive pulse with flexible voltage regulations. The power supply consists of an LC resonant converter as the charging network and a thyristor-based pulse forming network. Based on the proposed design approach, a 7 kW prototype is developed, which is able to output maximum voltage of 2.2 kV with a repetitive frequency ranged from 1 to 10 Hz. Moreover, the developed power supply is able to release up to 700 J of the energy on the xenon lamp.