Abstract: In this paper, titanium silicate-1 (TS-1) catalyzed ring-opening of propylene oxide in process of propylene epoxidation using alcohol as solvents was studied. The ring-opening is the side reaction of epoxidation. The acidic reaction mechanism and the effect of different alcohols on ring-opening reaction were discussed in detail. Acidity mainly originates from proton acid produced by the interaction of active sites of TS-1 with H2O2. Alcohol solvents can obviously enhanced acidity. The order of three alcohol solvents according to extent promote acidty is methanol>iso-propanol>sec-butanol. With assumption of Eley-Rideal mechanism that PO molecule absorbs on the catalytic site reacts with dissociated solvent molecule, and surface reaction is the rate-controlling step, also consider absorptivity of components on the TS-1, a mechanism model was proposed. After parameter estimation, relevant kinetics equation was obtained which well fit the experimental data. The average relative deviation between experimental and calculated reaction date is less than 10%.