Abstract: The emulsion polymerization of styrene(St) was firstly carried out by initiating of H2O2Fe2+ redox initiation system. PSt-OH was obtained with hydroxyl group as end group in polystyrene. Subsequently, the macromolecules PStOH were solubilizated in the micellar solution of sodium dodecylsulfate(SDS), and the block polymerization of Nvinylpyrrolidone(NVP) in the aqueous solution at the end group of PSt-OH was initiated by cerium ammonium sulfate, resulting in the amphiphilic block copolymer PSt-b-PVP. Several means were adopted to characterize the chemical composition and structure of PSt-b-PVP, such as FT-IR, 1H-NMR, GPC and DSC. Results show that by the oxidation action of cerium(Ⅳ) salt, free radicals can be produced at the sites of the hydroxyl groups of PSt-OH, which are solubilized in the micellar solution of SDS, and the block copolymerization of NVP can be favorably realized. With the increasing of copolymerization time, the content of PVP block is increased.