Abstract: Reduced graphene oxide (RGO) was synthesized via chemical reduction of graphene oxide (GO) with hydrazine hydrate. By adding RGO in blending system of the natural rubber(NR) and nitrile butadiene rubber(NBR), the RGO/NR-NBR composites were prepared by latex co-coagulation method. The structure and morphology of RGO were analyzed by FTIR, Raman spectroscopy, XRD and SEM. The results show that oxygen functional group can be removed by the reduction of GO with hydrazine hydrate, meanwhile, RGO has maintained the monolayer structure of GO. SEM images of RGO/NB-NBR composites indicate that RGO is homogeneously dispersed in composites and the stretching section of composites becomes rough obviously. Analysis on vulcanization characteristics indicate that the cross-linking density, maximum torque and torque difference of the RGO/NR-NBR composite increase with the RGO mass fraction increasing. The mechanical properties of RGO/NR-NBR compsites have been greatly improved after the addition of RGO. When RGO/NR-NBR composites with 3.0% RGO, the tensile strength, tensile strength at 100% elongation and the shore A hardness of RGO/NR-NBR composites increase by 65.7%, 90.3% and 21.1%, respectively; the elongation at break decreases by 13.1%.