The surface distortion of reflector mirrors in the laser cavity caused by high laser power changes the designed mirror surface that should be highly strict in the laser of good beam quality. The experiments show that both the copper reflector and the silicon reflector cooled by the thermoelectric refrigerator can compensate the distortion caused by laser power, so that the reflector surface is unchanged when it works. There are many other advantages of this kind of reflectors, such as no pressure distortion, the refrigerating power can be easily controlled and the cooling is even.