Electrically excited high power pulsed CO2 laser is one of the favorable lasers in novel applications such as laser propulsion. The performances of power and beam quality of the existed lasers cannot fulfill the requirements of these applications. The improvements of these performances are decided by the technologies of quick charging of high voltage capacitor, uniform discharge in high pressure large aperture zone, uniform flow of high pressure gas, and laser resonator, etc.. The technology of serial resonant switch mode power supply realizes the quick charging of high voltage capacitor with charging current of 807 mA, charging voltage of 50 kV for one unit. The inductor isolated Marx high voltage pulse generator is tested for the purpose of uniform discharge with a high pressure large aperture zone. By use of this method, the reliable working pressure of helium-free gas is increased from 2×104 Pa to 3×104 Pa, and the highest pulse energy is increased from 64 J to 115 J.