Abstract: In order to eliminate the effect of mass transfer the kinetics of o-xylene oxidation in liquid phase was studied in a stirring batch reactor. Experimentaldata indicate that the effect of mass transfer can be eliminted, when the stirring velocity is≥1200 rpm and the superficial velocity is≥1.5 cm/s at 130℃ under the experimental conditions. This paper recommends rate expression (suitable for conversion of o-xylene<50%)as kinetic model for scaling up gas-liquid reactors. The results of chemical reaction kinetics of o-xylene oxidation which involves both main and side reactions and contains seven components in total are presented. As with the bubbling reactor, the o-xylene oxidation reaction is composed of seversl consecutive and competitive 1-st order reactions.