Polybutylene terephthalate（PBT） samples of various color master batch（CMB） compositions were prepared via melt blending. The melting

crystallization

mechanical properties and after shrinkage were studied by means of melt flow rate measurer

differential scanning calorimeter（DSC） and mechanical tests. The results showed that the crystallization of PBT enhanced

crystallization peak shifted to higher temperature and after shrinkage enlarged

probably because the CMB acted as the nucleating agents. The tensile strength and flexural modulus increased

while the elongation at break and impact strength decreased with the increasing CMB content.