In order to improve the optical properties of the III-V laser diodes (LDs) by means of H2S plasma passivation technology, H2S plasma passivation treatment is performed on the GaAs(110) surface. The optimum passivation conditions obtained are 60-W radio frequency (RF) power and 20-min duration. So the laser cavity surfaces are treated under the optimum passivation conditions. Consequently, compared with unpassivated lasers with only AR/HR-coatings, the catastrophic optical damage (COD) threshold value of the passivated lasers by H2S plasma treatment is increased by 33%, which is almost the same as that of (NH4)2Sx treatment. And the life-test experiment has demonstrated that this passivation method is more stable than (NH4)2Sx solution wet-passivated treatment.