Seal gaskets are widely used in Proton Electrolyte Membrane (PEM) fuel cells to keep the reactant gases and liquid within their respective regions. High hardness and low compression set are both essential to seal performance of gaskets. However, the compression set usually increases with the increase of the hardness. Therefore, in this paper, EPDM seal materials with soft and hard alternating multilayered structure are fabricated through the multilayered co-extrusion system. The structure and morphology of multilayered and blended EPDM vulcanizates were observed by Scanning electron microscopy (SEM). The results of hardness, compression set and compression stress relaxation test show that multilayered vulcanizates have lower compression set but higher hardness than blended one. The compression set of multilayered vulcanizates decreases with the increase of the layer number, indicating better sealing capacity and longer working life. The results of aging test indicate that the mechanical properties of EPDM seal materials decrease with time, but multilayered vulcanizates still have lower compression set than blended one after aging.