Abstract: In this paper, EPDM was grafted with maleic anhydride and introduced into blends of poly(m-xylene adipamide)/polyamide 6 (MXD6/PA6） as a reactive compatibilizer forming a ternary blend (MXD6/PA6/EPDM). The compatibility of blended components was analyzed by Molau test. The rheological property, melting and crystallization behavior, and heat resistance of MXD6/PA6/EPDM blends were studied by HAAKE torque rheometer, differential scanning calorimetry, polarized light microscopy, and thermal gravimetric analysis. It was found that the addition of EPDM-g-MAH increased the balance torque of the blend system and the interfacial adhesion between MXD6 and PA6 was improved. EPDM-g-MAH lowered the nucleation density and the crystallization rate. The glass transition temperature and melting point of the blends decreased with increasing EPDM content，however, the thermal stability of blends was improved.