The surface chemical analysis of corroded alloys in the subcritical and supercritical water oxidation (SCWO) of 2-chlorophenol were studied by using a continuous anticorrosive SCWO system. The corrosion phenomenon of metal in the supercritical condition (250 atm and 380 degrees C) was different from that in the subcritical condition (220 atm and 320 degrees C). However, the corrosion of metal alloys contributed to the elevation of destruction efficiencies in both subcritical and supercritical conditions. Furthermore, the degree of improvement of destruction efficiency at the subcritical condition was higher than that at the supercritical condition regardless of alloy types. Although all the tested alloys were severely corroded under both conditions, the catalytic effect of Monel K-500 with Cu on the destruction of 2-chlorophenol was higher than the other alloys in both subcritical and supercritical conditions. The results indicated that well-selected metal alloys could be applied to both subcritical and supercritical oxidation as catalysts by corroding themselves.