In order to prepare the low permanent compression deformation seal materials for longterm use at 80 ℃, a thermoplastic polyurethane elastomer(TPU)were synthesized with polycaprolactone diol(PCL),4,4′diphenyl methane diisocyanate(MDI),Hydroquinone bis(2hydroxyethyl)ether(HQEE),1,4butanediol(BDO)as raw materials by prepolymer method.The effects of polymerization temperature,mass ratio of chain extender and isocyanate index on the mechanical properties and dynamic mechanical properties of TPU were studied.The results show that with the increasing of polymerization temperature,the tensile strength and tear strength are improved,the TPU synthesized at the polymerization temperature of 120 ℃ has the best mechanical properties.With the increasing of isocyanate index,the tensile strength is increased,the tear strength is first increased and then decreased,the compression set is first decreased and then increased,the degree of microphase separation is reduced,elastic hysteresis is increased.With the increasing of the ratio of HQEE and BDO chain extenders,the hardness and resilience rate are gradually increased,the tensile strength and the tear strength are increased first and then decreased,the permanent compression deformation is decreased first and then increased,the micro phase separation degree is increased,and the elastic hysteresis is reduced.The synthesized TPU has the minimum permanent compression deformation of 21% at 80 ℃ and 70 h when the mass ratio of HQEE/BDO is 80/20.