Heterogeneously-catalyzed oxidation of aqueous phase trichloroethylene (TCE) over supported metal oxides has been conducted to establish an approach to eliminate ppm levels of organic compounds in water. A continuous flow reactor system was designed to effect predominant reaction parameters in determining catalytic activity of the catalysts for wet TCE decomposition as a model reaction. 5 wt.% CoOx/TiO2 catalyst exhibited a transient period in activity vs. on-stream time behavior, suggesting that the surface structure of the CoOx might be altered with on-stream hours; regardless, it is probable to be the most promising catalyst. Not only could the bare support be inactive for the wet decomposition reaction at 36 ℃, but no TCE removal also occurred by the process of adsorption on TiO2 surface. The catalytic activity was independent of all particle sizes used, thereby representing no mass transfer limitation in intraparticle diffusion. Very low TCE conversion appeared for TiO2-supported NiOx and CrOx catalysts. Wet oxidation perfor-mance of supported Cu and Fe catalysts, obtained through an incipient wetness and ion exchange technique, was dependent primarily on the kinds of the metal oxides, in addition to the acidic solid supports and the preparation routes. 5 wt.% FeOx/TiO2 catalyst gave no activity in the oxidation reaction at 36 ℃, while 1.2 wt.% Fe-MFI was active for the wet decomposition depending on time on-stream. The noticeable difference in activity of the both catalysts suggests that the Fe oxidation states involved to catalytic redox cycle during the course of reaction play a significant role in catalyzing the wet decomposition as well as in maintaining the time on-stream activity. Based on the results of different CoOx loadings and reaction temperatures for the decomposition reaction at 36 ℃ with CoOx/TiO2, the catalyst possessed an optimal CoOx amount at which higher reaction temperatures facilitated the catalytic TCE conversion. Small amounts of the active ingredient could be dissolved by acidic leaching but such a process gave no appreciable activity loss of the CoOx catalyst.