With the continuous expansion of the array scale of infrared focal plane detectors, the thermal stress of large array HgCdTe chips becomes worse. The damage is prone to occur after temperature shock, which will directly affect the use of the detectors, and even lead to the failure of the detectors. This has become an urgent problem to be solved in the production process of large array detectors. In this paper, the damage reason of large array HgCdTe chips at low temperature is studied by means of simulation, and the comparison analysis is made with small array detectors. The results show that the stress concentration locates at the edge of indium column and HgCdTe, which is the origin of the damage. The selection of different materials and the design of the structure sizes are helpful to reduce the thermal stress and improve the reliability of large array HgCdTe chips.