The CO₂ laser quenching treatment was used to study the surface modification of a gear counter. In the present investigation, the two hardening the counter gear approaches were compared by the CO2 laser. It was found that the two approaches of laser quenching were effective to enhance the surface microhardness to HV412 -HV550 . Meanwhile, the microhardness distribution was measured . After the laser heat treatment ,the depth of laser hardening was 1. 0mm, the highest microhardness HV680 was higher HV160 than the common oil quenching. The value of surface roughness before quenching was not found to change with comparison to that after quenching treatment. It is shown that the distortion of surface upon laser quenching was remarkably induced to 2. 5μm. In addition, the microstructure of 3Cr13 stainless steel after laser quenching and high frequency induction quenching was observed. After laser quenching, the fine martensite structure was obtained.