Abstract: The polyol macromers were prepared by esterification reaction of polyol and maleic anhydride under a variety of temperatures and reaction times, and were charactrized by UV and FT-IR. The graft copolymers were synthesized by free radical copolymerization of these macromers and styrene. The products of graft copolymer were separated carefully and characterized by FT-IR and ~1H-NMR. The experimental data showed that the graft efficiency of styrene for these copolymerization systems is appreciably increased with decreasing the temperature. For using a redox system(BPO/DMA) at a low temperature (303K), the graft efficiency of styrene was as high as 0.58 observed.