Poly (trimethylene terephthalate) was melt-blended with Maleinized acrylonitrile-butadiene-styrene to enhance its toughness without sacrificing comprehensive performance. The advantage of using ABS-g-MAH is due to its high toughness, good processing properties and higher molecular polarity. The phase morphology, mechanical properties, crystallization behaviors, dynamic mechanical behaviors, rheology, spherulites morphology, thermal stability and thermal aging properties were investigated by scanning electron microscopy (SEM), universal tester, differential scanning calorimetry (DSC), dynamic mechanical analyzer (DMA), capillary rheometer, polarized optical microscopy (POM), thermogravimetric analyzer and color-difference meter, respectively. The results suggest that the dimension of the dispersed phase is lower than 1 ïm and the interface between ABS and PTT is unsharp; therefore, ABS is compatible with PTT. With addition of 5%ABS, the yielding strength, breaking strength and impact strength of the blends increase 41.5%, 167% and 200% than those of pure PTT; therefore, ABS can not only greatly toughen PTT but also reinforce PTT to some extent with proper additions. ABS also serves as a nucleating agent for increasing the crystallization rate. The blends show larger storage modulus and higher glass transition temperatures than those of pure PTT.ABS improves the processing property of PTT by increasing the apparent viscosity of the blends. However, the blends of PTT/ABS showdecreased thermal aging resistance of the blends.