Abstract: The physical and electrochemical behaviors of the tantalum substrate born-doped diamond (Ta/BDD)electrode prepared by hot filament chemical vapor deposition (HFCVD) technique and its application in electrochemical oxidation of wastewater containing nitrophenol were studied. Raman spectroscopy and scanning electron microscopy (SEM) examinations demonstrated that the electrode had well-defined diamond features. It was observed that the Ta/BDD electrode had a much higher overpotential for water electrolysis prohibiting the evolution of oxygen in the cyclic voltammetry test. During the electrochemical oxidation of wastewater containing nitrophenol, the results obtained by high performance liquid chromatography (HPLC) and chemical oxygen demand (COD) tests showed that the electrochemical process was suitable for completely degrading nitrophenol. The influence of current density, temperature, support electrolyte, and electrolyte concentration was investigated in order to find the best conditions for COD removal. od electrochemical stability of Ta/BDD electrode was obtained in the accelerated life test. According to the results, Ta/BDD anode is consitered to be a unique electrode for the degradation of nitrophenol and COD simultaneously.