The photocatalytic degradation characteristics of TCE, acetone, and toluene have been determined in a circulating fluidized bed (CFB) photoreactor system over TiO2/silica gel photocatalyst. The conversions or acetone and toluene decrease with the initial acetone and toluene concentrations in the CFB reactor. Water vapor enhances the photo-degradation rate of toluene, but inhibits it for trichloroethylene (TCE) and acetone. The photocatalytic conversions of TCE and acetone exhibit it maximum value at 318 K but that of toluene exhibits a maximum value at 298 K. The optimum oxygen concentration for the maximum degradation of acetone and toluene are found to be approximately 10% and 7%, respectively. The present circulating fluidized bed (CFB) photoreactor system is an effective tool for higher degradation of volatile organic compounds (VOCs) with efficient utilization of photon energy.