Tantalum-based diamond film electrode is found having wider potential window and better catalyzing-oxidation efficiency by testing its electrochemical performance. By examining electrochemical degradation performance of tridecane dicarboxylic acid organic wastewater on these electrodes, the effect of various technique conditions on the COD removal, including potential, electrolysis time, the distance of two electrodes, pH value and with and without stirring, are investigated. The result shows that COD removal rate is 99% and meets the discharge standard of China. The specific electricity consumption is 6.4 kWh/kg COD. The proper technique conditions are 1.6 V potential, 7 h electrolysis, 20 mm distance of the two electrodes and pH value from 3 to 5.