Abstract: This paper investigates the degradation of chlorobenzene by dielectric barrier discharge (DBD) coupled with MnOx/γ-Al₂O₃ catalysts. MnOx/γ-Al₂O₃ catalysts were prepared using the impregnation method and were characterized in detail by N₂ adsorption/desorption, x-ray diffraction and x-ray photoelectron spectroscopy. Compared with the single DBD reactor, the coupled reactor has a better performance on the removal rate of chlorobenzene, the selectivity of CO_x, and the inhibition of ozone production, especially at low discharge voltages. The degradation rate of chlorobenzene and selectivity of CO_x can reach 96.3% and 53.0%, respectively, at the specific energy density of 1350 J l^–1. Moreover, the ozone concentration produced by the discharge is significantly reduced because the MnOx/Al₂O₃ catalysts contribute to the decomposition of ozone to form oxygen atoms for the oxidation of chlorobenzene. In addition, based on analysis of the byproducts, the decomposition mechanism of chlorobenzene in the coupled reactor is also discussed.