In order to exploit the biological functions of materials, a series of new random terpolymers were synthesized by the ring-opening polymerization of p-dioxanone, trimethylene carbonate, and L-phenylalanine N-carboxyanhydride(L-PheNCA) in the presence of stannous octoate. The terpolymers were characterized by 1H-NMR, 13C-NMR, FTIR, and gel permeation chromatography. The effects of the reactant ratio, catalyst dosage, reaction temperature and time on the copolymerization were investigated, and were found to regulate the composition of the terpolymer. Increases in the reaction temperature, polymerization time, L-Phe-NCA monomer amount, and catalyst content generated a product with a slightly decreased molecular weight. The crystallinity of the terpolymer was investigated by differential scanning calorimetry and polarized optical microscopy. A reasonable mechanism for the polymerization was proposed based on the obtained results. In order to exploit the biological functions of materials, a series of new random terpolymers were synthesized by the ring-opening polymerization of p-dioxanone, trimethylene carbonate, and L-phenylalanine N-carboxyanhydride (L-PheNCA) in the presence of stannous octoate The terpolymers were characterized by 1H-NMR, 13C-NMR, FTIR, and gel permeation chromatography. The effects of the reactant ratio, catalyst dosage, reaction temperature and time on the copolymerization were investigated, and were found to regulate the composition of the Increases in the reaction temperature, polymerization time, L-Phe-NCA monomer amount, and catalyst content generated a product with a decreased molecular weight. The crystallinity of the terpolymer was investigated by differential scanning calorimetry and polarized optical microscopy. mechanism for the polymerization was proposed based on the obtained results.