Abstract: Syndiotactic polystyrene (sPS) was prepared by bulk polymerization with homogeneous metallocene catalystic system, Cp*Ti(OPh)₃ or Cp*Ti(OPhOMe)₃/MAO/TIBA.It was found that a fast crystallization of the produced sPS is very important to avoid gelation of the polymerizing mixture and prepare powdery product.But, it was due to crystallization nucleation mechanism that the morphology of produced particles was very irregular and extraordinarily difficult to manipulate.Adding a little sPS seed during polymerization did not improve particle morphology.However, regular particles with good morphology could be simply prepared by adding a little other polymer.When the added polymer (e.g. mEPDM) was immiscible with the amorphous sPS,spherical particles could be obtained.