Isothermal and non-isothermal crystallization kinetics of a syndiotactic polypropylene(sPP) sample synthesized by new metallocene catalyst at different annealing temperatures and different cooling rates have been investigated by using differential scanning calorimetry(DSC) and density analysis.The equilibrium melting temperature(T0m) is 158 by Hoffman-Weeks method.The equilibrium heat of fusion(H0m) is 88J/g in terms of the density analysis and DSC methods. The lateral and end surface free energies derived from the Lauritzon-Hoffman spherulitic growth rate equation are σ=5.2erg/cm2 and σe=69erg/cm2

respectively.The work of chain folding is determined to be q=33.75kJ/mol.Modified Avrami equation and Ozawa equation canbe used to describe the non-isothermal crystallization behavior.And a new and convenient approach by combining the Avrami equation and Ozawa equation in a same crystallinity is used to describe the non-isothermal behavior as well.The crystallization activation energies are evaluated to be 73.7kJ/mol and 73.1kJ/mol for isothermal crystallization and non-isothermal crystallization

respectively.The Avrami exponent nt is 1.5～1.6 for isothermal crystallization procedure

while the Avrami exponent nt

is 2.5～3.5 for non-isothermal crystallization procedure.This indicated the difference of nucleation and growth between the two procedures.