Abstract: The cryogenic insulation support（POST） is a key component related to the cold mass in the cryomodule of ADS accelerator, playing a crucial role in the fixed support, static heat leakage, precision alignment, and cryogenic shrinkage of cold mass. The relationship of POST is introduced between interference and contact stress. Thermal and mechanical coupling analysis of POST is studied by finite element. The contact stress changes of POST during the cooling process are calculated, and the deformation of glass fiber cylinder in different states is studied. The POST tensile test results are analyzed. This provides a theoretical basis and research reference for subsequent optimization design.