Rare earth oxides modified composites were prepared using HNBR as the substrate,and the effects of rare earth oxide types and dosages on the mechanical properties and hot air aging proper-ties of the composites were studied.The results showed that the addition of a certain amount of lantha-num oxide or cerium oxide could significantly improve the mechanical properties and hot air aging properties of the composites.The addition of 2 phr of cerium oxide could greatly improve the tensile strength,tear strength and hot air aging properties of the composites.