The effects of nylon 6 matrix viscosity and a multifunctional epoxy interfacial modifier on the notched impact strength of the blends of nylon 6 with a maleic anhydride modified polyethylene-octene elastomer/semi-crystalline polyolefin blend (TPEg) were studied by means of morphological observation, and mechanical and rheological tests. Because the viscosity of the TPEg is much higher than that of nylon 6, an increase in the viscosity of nylon 6 reduces the viscosity mismatch between the dispersed phase and the matrix, and increases notched impact strength of the blends. Moreover, addition of 0.3 to 0.9 phr of the interfacial modifier leads to a finer dispersion of the TPEg and greatly improves the notched impact strength of the nylon 6/TPEg blends. This is because the multi-epoxy interfacial modifier can react with nylon 6 and the maleated TPEg. The reaction with nylon 6 increases the viscosity of the matrix while the coupling reaction at the interface between nylon 6 and the maleated TPEg leads to better compatibilization.