The blends of poly (trimethylene terephthalate)(PTT) and maleinized poly (octene-ethylene) copolymer (POE-MAH) were prepared by melt-blending method and their rheology and thermal stability were investigated by using rotational rheometer and thermalgravimetric analyzer (TGA) respectively. The rheological properties of PTT/POE-MAH blends demonstrate that all of the blends belong to the pseudoplastic fluid for their complex viscosity declines with the increasing shear rate. In addition, POE component can strengthen the melt viscosity, so the blend can be processed in the more wider temperature range. Moreover, the complex viscosity become more sensitive to the change of the shear rate, i.e., it decreases more apparently with the increase of the POE-MAH component. The melt flexibility increases apparently with the increase of the POE-g-MAH component. POE-MAH component only has a little depression on the thermal stability of the blends.