The low temperature resistance of castable laminated polyurethane bearings（CLPB） was improved by introducing 3-methyl-tetrahydrofuran/tetrahydrofuran copolyether glycol（3MCPG）. The mechanism of the effect of different 3MCPG mass fractions （0%， 6%， 9%， 12%， 15%， and 25%） on the polyurethane elastomer（PUE） was investigated at the microscopic level， and a series of mechanical experiments were conducted at 23， 0， -10， -20 ℃ for the modified PUE and CLPB， respectively. The results show that， by the introduction of 3MCPG， the degree of microphase separation and glass transition temperature of the soft and hard segments of PUE are reduced. Compared to the tensile strength at 23 ℃， the tensile strength of PUE-0% and PUE-25% at -20 ℃ is increased by 50.8% and 20.1%， and the vertical stiffness of CLPB-15% and CLPB-25% compared to that of CLPB-0% is decreased by 2.5% and 4.4%， and the horizontal stiffness of CLPB-0% and CLPB-25% is increased by 106.0% and 44.2% at -20 ℃， respectively.