The phase morphology and dynamic rheology of poly (trimethylene terephthalate)/maleinized poly (octene-ethylene)/organo-montmorillonite nanocomposites were investigated by using transmission electron microscopy (TEM) and rotational rheometer. The results suggest that some of the OMMT are peeled off and the nanosheets are dispersed evenly in the polymer matrix. When the OMMT content is more than 4%, they are tended to form the aggregates in nanocomposites. The nanocomposites’ melt are pseudo-plastic fluid, and both complex viscosity and shear storage modulus increase with increasing OMMT content due to the interaction between the OMMT and polymers. The nanocomposites’ melt show more elasticity behavior with more OMMT content especially at low shear frequencies.