Abstract: Under water removed by certain N<sub<2</sub< flow rate, PGS was prepared from glycerol and sebacic acid with equal molar ratio. To optimize N<sub<2</sub< flow rate and reaction temperature, the products were analyzed by FTIR, acid value, intrinsic viscosity (<em<η</em<), gel permeation chromatography (GPC), and <sup<1</sup<H NMR. The optimized reaction condition was confirmed as N<sub<2</sub< flow rate of 0.1 m<sup<3</sup</h, polymerization temperature of 160 ℃ and reaction time of 7.75 h. PGS obtained under this condition was with carboxyl esterification percent of 90.3%,<em<η</em< of 42.0 mL/g, <em<M</em<<sub<n</sub< of 2 200 and <em<M</em<<sub<w</sub< of 249 800. The mass percent of fraction with molecular weight over 10 000 and 3 000 were 50.5% and 71.5%, respectively. The results indicate that high molecular weight PGS can be economically synthesized using this method.