Poly(pentamethylene terephthalate)(PPT) was synthesized by direct esterification polycondensation．The molecular structure of the product polymer was confirmed by 1H-NMR and IR measurements．The intrinsic viscositv of the PPT sample was 0.878 dL/g in a mixture solvent of phenol/tetrachloroethane (1：1 by wt) at 25℃ The crystallization of PPT was analyzed with DSC．Compared with poly(trimethylene terephthlate)(PPT)

PPT has lower glass transition temperature (14℃) and melting point(129℃) and higher cold crystallization temperature(85℃)．The kinetic analysis of isothermal crystallization processes showed that the crystallization rate of PPT is lower than that of PET．The crystallization of PPT was heterogeneously nucleated and exhibited threee dimensional growth of sphertdites．Thermogravimetry analysis showed that the decomposition temperature of PPT is 383℃．sanle as that of PPT.