Structural stress issues in mercury cadmium telluride (HgCdTe) infrared detector chips caused by thermal mismatch under cryogenic conditions are systematically investigated by integrating experimental measurements with finite element simulations.A direct measurement technique based on low temperature strain gauge is developed,enabling real time monitoring of strain and stress during the cooling process of a 640×512 HgCdTe chip.A maximum contraction strain of 1042 με and a maximum stress of 69 MPa are measured.A thermo mechanical coupling model of the detector module is established using ANSYS finite element simulations,revealing stress concentration in the central region (maximum simulated stress:63 MPa) and lower stress levels at the periphery.The relative error between numerical simulations and experimental results is less than 20%,validating the model’s accuracy.Simulation efficiency is improved through simplified modeling of indium columns and homogenization treatment,providing theoretical support for optimizing detector packaging structures.The study demonstrates that the combined experimental corrected numerical simulation method can significantly shorten design cycles and optimizes low stress packaging solutions.Consequently,the risk of chip cracking is reduced,and device reliability is enhanced.