The 2-chlorophenol (2-CP) was decomposed in a continuous anti-corrosive supercritical water oxidation (SCWO) system. The effect of the corrosion of zirconium 702 on the decomposition efficiency was studied at the various conditions of feed concentration and reaction time. The surface chemical analysis of the corroded zirconium exposed to the SCWO was performed by the AES-SAM. According to AES depth profile, the oxygen penetration depth to zirconium was not proportional to the exposure time. It might be stemmed that the formation of zirconium oxide layer on the surface delayed the corrosion. However, the increase in feed concentration accelerated the corrosion of zirconium. The corrosion of zirconium at low feed concentration led to the improvement of decomposition efficiency due to the catalytic work of formed zirconium oxides while that at high feed concentration deteriorated the decomposition efficiency owing to large consumption of oxidant in corrosion.