The synthesis of a diblock copolymer of styrene and vinyl acetate (VAC), PS-b-PVAC, was performed by successive photoinduced charge-transfer polymerization (CTP) under UV irradiation. A novel amphiphilic diblock copolymer of PS-b-PVA then was obtained by the hydrolysis of the diblock copolymer PS-b-PVAC with sodium ethoxide as a catalyst. Both of them were characterized by Fourier transform infrared, H-1 NMR, and gel permeation chromatography in detail. The effect of the solvents on the CTP and the kinetics of the CTP are discussed.