Abstract: Aiming at the EPDM used usually as the ablation resistant material on the inner surface of the rocket case, the influence on EPDM rubber aging performance of vulcanization system, such as sulfur vulcanization, sulfocompound vulcanization and peroxide vulcanization, was studied in this paper. And the surface topography, relative content of surface components and mechanical properties such as compression permanent deformation and compressive stress relaxation of peroxide vulcanization EPDM before and after the hot oxygen aging were studied with SEM micro analysis and macroscopic mechanics experiment. The results show that, peroxide vulcanization system can make the C-C crosslinked bond which have more stable performance generated inside the EPDM rubber, and the heat-resisting performance is better than the other two. The pyrolysis of EPDM rubber is one-step reaction, the weight loss of each temperature stage, the total weight loss of whole temperature range and the maximum thermal decomposition temperature show no obvious difference between the nonaging and aging samples. Through the surface components analysis, the plasticizer (dibutyl sebacate) migration is found on the surface of aging samples, but there is no obvious volatility. For peroxide vulcanization EPDM rubber, the performance of compression permanent deformation retention rate, compression stress relaxation and tensile strength have a certain degradation, and the higher aging temperature, the greater degree of change.