Grain poly(ethylene terephthalate) (PET) was depolymerized in pure water by different metal oxides, respectively. The catalytic hydrolysis product of terephthalic acid (TPA) obtained was the same with the no catalytic reaction. The depolymerization rate of PET was seriously influenced of the reaction time and temperature. Especially using stannous oxides as catalyst, with a reaction time of 210 min, a temperature of 200 degrees C and a pressure of 200 psi, the depolymerization rate of PET increased from 59.3 to 90.9% compared with the no catalytic reaction. The morphology of the solid residue indicated that the depolymerization took place on the external surface of the PET grain in the presence of stannous oxide. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 117: 3155 3159, 2010