Abstract: A wire-plate dielectric barrier discharge combined with catalysts was used to remove toluene. The effects of background gas, loading position of catalysts as well as humidity on the removal of toluene and ozone were investigated. It was found that the energy density was increased with the catalyst in plasma. When the catalyst was placed in plasma, the high removal efficiency of toluene and ozone was realized because of the catalysis of oxygen species. Comparing the catalyst loaded in the back end with the front end, higher toluene removal efficiency and less ozone production was realized. Humidity had both positive and negative influence on the removal of toluene in plasma system. With increase of humidity, the removal efficiency of toluene first increased and then decreased. The toluene and ozone were removed simultaneously with the catalyst in post-plasma. In plasma catalysis system, the decomposition of toluene was initiated by high energy electron and radicals, and the main products were CO, CO2 and H2O, and the by-products were alkanes, acids, aldehyde and benzene-ring organic compounds in gaseous phase.