The amount of CO and NO, formed during the electric discharge of the JL6A type CW high power transverse flow CO2 laser have been determined. The catalysts Pd-Ni/r-Al2O3 and the rare earth perovskite-type compounds (ABO3) are used for the elimination of both CO and NOa. For the ABO3 catalysts, conversion rate of CO is 85.1% and NO, 63.1% when the gas space velocity is 15,000 h-1 and the temperature is 260℃.