Poly(m-xylylene adipamide)/poly(ethylene terephthalate) (MXD6/PET) copolymers are synthesized by melt copolycondensation with 1-5 wt% low molecular weight PET oligomers into the MXD6 oligomers at 260 degrees C. FR-IR and H-1 NMR analysis results indicate that the interchange reaction has occurred between MXD6 oligomers and PET oligomers. The thermal behavior of copolymers shows that the melting temperature of MXD6/PET copolymers decreases with the increasing of amount of PET oligomers, while the crystallization temperature accordingly increases. And the equilibrium temperature T-m(0) is evaluated to be 251.8 degrees C for the copolymers with 5 wt% PET oligomer adding, which is very close to that of neat MXD6. The tensile and impact strength of MXD6/PET copolymers are significantly improved than that of pure MXD6 by mechanical properties test, and the microfibril structure in the impact fracture sample's surface reveals the feature of ductile fracture. (C) 2016 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.