In order to solve the problem of Catastrophic Optical Damage (COD) caused by the rapid rise of the cavity surface temperature during the long-term high temperature operation of the laser, it is proposed that the addition of Al₂O₃ coating and the thermal insulation structure together at the semi-conductor laser surface, it can reduce the temperature of laser cavity surface and prevent the generation of COD. First, a simplified semi-conductor laser model is established to analyze solid heat transfer. Then, the cavity surface temperature of the laser model is simulated at 550 K when there is no coating and no insulation structure, coating and no insulation structure, no coating and insulation structure, and when the coating and insulation structure act together, the ceramic heat insulation is used in the heat insulation structure, GaAs is used in the cavity surface material, Cu is used in the heat sink and AlGaAs is used in the contact layer. The results of 4 groups of contrast experiments show that the temperature of the cavity surface can be controlled below 393.15 K when the coating and the thermal insulation structure act together. 550 K high temperature in the laser cavity surface coating and thermal insulation structure under the dual protection, can effectively prevent the generation of COD, so that the life of the laser can be improved.