In this article, we prepared styrene-butadiene-styrene grafted multi-walled carbon nanotubes/epoxy (SBS-g-MWNTs/EP) nanocomposites by modifying the curing agents of epoxy. Methylhexahydrophthalic anhydride (MHHPA), 2-Ethyl-4-methylimidazole (EMI-2,4) and multi-walled carbon nanotubes (MWNTs) were composed of a new type curing agent of epoxy, in which to enhance the compatibility between MHHPA and MWNTs, styrene-butadiene-styrene grafted MWNTs (SBS-g-MWNTs) were prepared by a solution method to replace pure MWNTs. Then the SBS-g-MWNTs were characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform-infrared spectroscopy (FT-IR), scanning electron microscope (SEM), and transmission electron microscopic (TEM). The influence of SBS-g-MWNTs on the epoxy nanocomposites were investigated by thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), and the tensile, flexural and impact test. The results indicated that the anhydride groups in SBS-g-MWNTs could be homogeneously mixed into MHHPA, so that it would be better dispersed in the epoxy matrix. Therefore, the mechanical and thermal properties of the nanocomposites had been improved significantly. POLYM. COMPOS., 39:E996-E1004, 2018. (c) 2017 Society of Plastics Engineers