Super toughened poly(trimethylene terephthalate) (PTT) blend was obtained by melt blending of PTT with a flowable crosslinked elastomer blend. The elastomer blend was prepared through reaction between an epoxy contained ethylene acrylate copolymer (EMMA-GMA) and an ethylene acrylic copolymer with carboxylic acid and zinc ion (EMAA-Zn). The EMMA-GMA/EMAA-Zn elastomer with rich epoxy groups was found to be an effective impact modifier in PTT resin because the zinc ion in the elastomer catalyzed the reaction between the epoxy and end groups of PTT resin to promote the interfacial compatibilization between the PTT matrix and the crosslinked elastomer phase. It was found that a homogeneous and moderate dispersed size was achieved in the super toughened PTT/(EMMA-GMA/EMAA-Zn) blend due to the improvement of interfacial miscibility and the increase of viscosity ratio of crosslinked elastomer to PTT. POLYM. ENG. SCI., 58:2039-2046, 2018. (c) 2017 Society of Plastics Engineers