The surface modification of graphene oxide was carried out with dodecylbenzene, and the π‐π noncovalent interaction was introduced between the interfaces of graphene oxide and dodecylbenzene. The modified graphene oxide was added to ethylene‐propylene‐diene monomer by mechanical blending, and then the ethylene‐propylene‐diene monomer/modified graphene oxide vulcanizate was prepared. The results show that the dodecylbenzene loading rate on the surface of graphene oxide was about 40%. The addition of the graphene oxide and the modified graphene oxide was both beneficial to improve the thermal stability of the ethylene‐propylene‐diene monomer, but the effect of the modified graphene oxide was better. The addition of graphene oxide would cause the glass transition temperature of vulcanizate to shift toward higher temperature. However, the addition of modified graphene oxide would result in the glass transition temperature of vulcanizate to shift toward lower temperature. The tensile strength and elongation at break of vulcanizate would be improved simultaneously with the addition of modified graphene oxide. The reason was related to the slipping of dodecylbenzene on the surface of graphene oxide and the destruction of π‐π non‐covalent bonds at dodecylbenzene‐graphene oxide interfaces. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48261.