Star-shaped PMMA-b-PS block copolymers with POSS core were prepared by atom transfer radical polymerization of St using star-shaped POSS/PMMA-CI as a macroinitiator in presence of CuCl, 2,2,-bipyridine, toluene at 110 degrees C. The core-first method, which used an active multifunctional core to initiate the growth, of polymer chains, was applicable to making star-shaped block copolymers with POSS core. The structure of hybrid star-shaped PMMA-b-PS block copolymers was characterized by GPC and H-1 NMR, respectively.