Abstract: The depolymerization of polytrimethylene terephthalate in methanol was carried out in an autoclave reactor. The effects of reaction temperature and reaction time on the reaction were investigated. The results showed that the yields of monomers were dependent on the reaction temperature and reaction time. The variation of carboxymethl group in the solidproducts were analyzed by gel permeation chromatograph. A kinetic model was used to describe the reaction, which fitted well with the experimental data. The dependence of rate constant on the reaction temperature was correlated by the Arrhenius plot giving the activation energy of 87.8kJ/mol.