The microsphere copolymer [poly(St-co-HEMA)] of monodispersed styrene and 2-hydroxyethyl methacrylate(HEMA) was synthesized by suspension polymerization. New type of hydrophobic microsphere was synthesized by surface grafting polylactic acid using the hydroxyl-terminated of poly (St-co-HEMA) as initiator. The microspheres’ structures and properties were characterized by FT-IR, SEM and thermogravimetric analysis. The results have demonstrated that the copolymer [poly(St-co-HEMA)] is a random copolymer. The volume of the polylactide which was grafted with the microspheres can be controlled by changing the amount of microspheres and hydroxyl in microspheres.