To improve the stability and reliability of the rotated spark switch system in a high power Transversely Excited Atmospheric(TEA) CO2 laser and to reduce the volume and weight of a trigger system for the rotated spark switch, this paper induces the series resonant charging technology into the trigger system. A high-frequency high-voltage charging power supply consisting of a full bridge inverter circuit and a series resonant soft switch circuit is developed. The charging power supply is taken as a trigger system for the rotated spark switch and offers a output voltage greater than 38 kV and a output power of 2 kV. In this system, the full bridge inverter circuits consist of Intelligent Power Models(IPMs), and the MSP430 is used to control the frequency, pulse width and the number of pulses for IPM driving signals. After full-bridge inverter circuit and series-resonant circuit get the pulse signals, it will charge for a high voltage capacitor by increasing the voltage and rectifying for a high-voltage pulse transformer. When the voltage reaches the hold-voltage of spark switching, the capatior discharges. The results suggest that the system can continuously and stably trigger the rotated spark switch when the Pulse Repetition Frequency(PRF) is 500 Hz. As a result, the system enhances the stability and reliability of triggering rotated spark switch and reduces the volume and weight of the system by 1/2 that of a pulse trigger system.