The performance improvement of IrO2 electrode for the oxidative destruction of organics through evaluations of the electrode in terms of material, electrochemical, and destruction organic properties has been carried out by using TGA, XPS, AES, and TOC measurement of 4CP organic destruction at the electrode. A sintering temperature of around 650 degreesC rather than 400-550 degreesC suggested in the literature for the Ir oxide electrode enhanced the organic destruction yield because the electrode surface was sufficiently converted to IrO2 from the IrCl3 of the precursor solution. An additional oxide layer between the IrO2 layer and the Ti substrate, to prevent a solid diffusion of TiO2 due to oxidation of the Ti substrate during high-temperature sintering, further improved the organic destruction so that the 4CP destruction yield raised to about four times higher than that by the conventional Ir oxide electrode. The destruction yield of 4CP solution with chloride ion at the improved electrode increased as much as that by an RuO2 electrode sintered at 430 degreesC in the same solution. The improved Ir oxide electrode had a long lifetime and good production of active chloride compounds.