A polytetramethylene ether glycol system polyurethane elastomer that meets the TBM main drive sealing requirements was prepared. Based on the working condition of the TBM main drive seal lacking oil lubrication, the wear morphology, wear chemical changes and failure mechanism of the elastomer under different dry friction conditions are mainly explained. The results show that the hydrogen bond content and molecular structure of soft and hard segments of polyurethane elastomer will change when the friction temperature increases, leading to a decrease in mechanical properties and wear failure. With the increase of rotation speed and load, there are different temperature rise trends, wear morphologies and mechanisms, and there is an obvious sudden temperature rise before wear failure, which can be used as an important criterion for seal failure monitoring.