Styrene-ethylene-butadiene-styrene (SEBS) copolymer grafted graphene oxide/epoxy (SEBS-g-GO/EP) nanocomposites were successfully prepared by modifying the curing agents of epoxy resin. To enhance the dispersity of graphene oxide (GO) itself and improve the compatibility between GO and polymer matrix, SEBS-g-GO was prepared via solution mixing technique, amination and following reaction with maleic anhydride grafted SEBS (SEBS-g-MAH), resulting in grafting rate 49 wt%. A series of characterization methods included the X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform-infrared spectroscopy (FT-IR), scanning electron microscope (SEM) and transmission electron microscopic (TEM) were used to confirm the grafting of SEBS onto GO. The effects of SEBS-g-GO on epoxy resin (EP) nanocomposites were investigated by thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), tensile, flexural and impact test. The results showed that SEBS-g-GOcould be uniformly dispersed in the epoxy resin matrix. The tensile strength, flexural modulus and impact strength of epoxy nanocomposite with 0.3 wt% SEBS-g-GO are 109.05%, 51.61% and 139.32% higher than that of pure epoxy resin, respectively. [GRAPHICS] .