Abstract: The long-term aging is rarely considered in the analysis of the rubber seal performance. This paper establishes a theoretical model of rubber seal performance analysis with consideration of the thermal oxygen aging based on the time-temperature equivalent theory. The influence of the compression rate and the performance change index on the contact performance of the rubber seal is investigated by using the model. The functional relationship is established between the calculated average contact pressure and the tested leakage rate of the rubber seal. The leakage rates, predicted by the function, are compared with the test results. Finally, the fitted relationship between the leakage rate and the aging time is obtained, and an accurate prediction of the rubber seal lifetime can be made by extrapolation.