Muti-layer theoretical Model of HgCdTe Infrared Focal Plane Device was established.With the method of finite element analysis,temperature field and thermal-stress field induced by 10.6 μm laser were simulated.By considering experiments carried out in other papers as reference,the rationality and feasibility of the muti-layer model are proved.Results of theoretical analysis indicates that the temperature field changes greatly when irradiated by laser.With CW laser of 200 W/cm2 power density irradiating the sensor for 1 s,thermal-stress of HgCdTe photo-sensitive surface is -986MPa;With pulsed laser of 100 ns and 15 MW/cm2 irradiating the sensor,thermal-stress of HgCdTe photo-sensitive surface is -1300 MPa.The thermal-stress mentioned above are both beyond that caused by thermal-mismatch in the production process.Besides,the probability of thermal-stress damage increases and may happen before thermal damage,which should be an important factor in the research of laser damage to HgCdTe Infrared Focal Plane Device.