A novel type of glycerol-derived, water-soluble polycarbonate with pendant, primary hydroxyl groups was prepared from 2-(2-benzyloxyethoxy)trimethylene carbonate (BETC). Ring-opening polymerization of BETC and 2,2-dimethyltrimethylene carbonate (DTC) gave narrow distribution of homopolymers or random copolymers with high molecular weights. The protecting benzyl groups were removed by catalyzed hydrogenation at atmosphere H-2 pressure to give hydroxyl polycarbonates without observable changes on the polymer backbone and molecular weight distribution. The hydrophilicity of the copolymers increases with the increase in the hydrophitic glycerol-derived carbonate content.