Abstract: Non-isot hermal crystallization behavior of polypropylene and high relative molecular mass nucleating agent(PNA) modified polypropylene was studied using differential scanning calorimet ry (DSC) with the data analyzed with Jeziorny method.Mechanical property of polypropylene and PNA modified polypropylene was studied using electronic universal testing machines. It showed that PNA increased the crystallization rate of PP , indicated by decreased t1/ 2 and increased Zc . t1/ 2 of polypropylene with 0.3 phr PNA decreased to 64.9 % than t1/ 2 of polypropylene. n of polypropylene decreased with cooling rate increased , and n of PNA modified polypropylene increased with cooling rate increased, tensile strength and impact strength of PNA modified polypropylene were higher than polyprolylene.