Photocatalysis system using plasma was prepared and performed. To overcome the treatment difficulty of high VOC concentration and continuous system, a strong intensity of plasma was used as a light source. As a result, much secondary products such as phenol, benzenediol, etc. were emitted at plasma only system than photocatalyst only system. Plasma-photocatalyst hybrid system was used to suppress secondary products resulting in enhanced CO2 selectivity. In order to maximize the CO2 selectivity, using of high porous material for hybrid system was essential. For this, in case of using gamma-Al2O3 as a support of catalyst, benzene conversion and selectivity to CO2 were dramatically enhanced. Finally, continuous mode plasma-photocatalyst hybrid system is quite useful for the treatment of large amount of VOC with high concentration. (C) 2004 Elsevier B.V. All rights reserved.