Abstract: In order to promote the compatibility between rubber graft and nylon 6 (PA6) and its toughening effect, the anhydride and p-phenylene diamine were used to compound a dicarboxylic acid containing an amide bond and named terephthalic diamide of maleic acid (modified maleic anhydride, MDMA).MDMA was grafted onto ethylene propylene diene monomer(EPDM) to prepare modified maleic anhydride grafted rubbers(EPDM-g-MDMA). EPDM-g-MDMA/PA6 blends containing different graft ratio grafts were prepared when mass ratio of EPDM-g-MDMA to nylon6 (PA6) is 30:70. MDMA was tested by NMR and FTIR for indicating the successful synthesis of the desired dicarboxylic acid. The results of compatibility test, DSC, melting index (MI) test, SEM, tensile and impact mechanical property tests of blends were preformed.Results show that with the graft ratio increasing, the melting peak temperature of the blend is slightly reduced, increasing the melt viscosity.The grafted rubber has good dispersion in PA6 matrix to make the impact strength of EPDM-g-MDMA/PA6 blends increased by 5.5 times, indicating EPDM-g-MDMA toughening PA6 effect is more obvious.