The basic structure and the materials thermal-stress properties of InSb infrared detector are introduced.The damage mechanism of InSb infrared detector caused by laser irradiation is elaborated.A 3D simulation model is built and related irradiation environment and condition are analyzed by using finite element method.The temperature changing and stress changing in each part of InSb infrared detector under CO2 laser irradiation with a wavelength of 10.6μm is simulated.The changes of temperature field and the stress field along the surface radial direction and the internal axial direction respectively under different laser power densities are compared by numerical analysis method when spot area is unchanged.The surface stress of the detector reached the highest point quickly after 106 W/cm2 laser irradiation,and then the detector is damaged.The stress value of the contact part between InSb and indium columns varied with the radius of laser spot.The accuracy of the InSb detector model is verified by comparing with the existing experimental data of stress damage threshold and changing trend.