The copolymerization of styrene (St) and styrene-terminated macromonomers with CpTiCl3-MAO catalyst was investigated. The contents of the macromonomer in the graft copolymer was found to depend on the miscibility of the macromonomer with the main chain polystyrene formed by copolymerization. miscible system of the syndiotactic polystyrene in the main chain and atactic polystyrene in the side chain was favorable for the incorporation of the macromonomer into the graft copolymer as compared with immiscible system of syndiotactic polystyrene in the main chain and atactic polyisoprene in the side chain. The contents of the SSTM in the graft copolymer was influenced by the MAO/Ti mole ratio and content of the SSTM in the comonomer feed.