B-doped diamond is an excellent grinding material owing to its high hardness, oxidation resistance and chemical inertness as well as low resistance. The recent developments of Boron doped conductive diamond has further increased the scale of diamond applications including the manufacture of electrically conductive grinding wheel or the use as an electrode in EDM. The unique electrochemical properties also attract the researchers’ attention on the applications of electrode, sensor and detectors etc. This paper presents a viable technology that high boron doped diamond is synthesized under high pressure and high temperature using B-doped GICs as carbon sources. The synthetic diamond grains with electrically resistivity of 2cm are sufficiently conductive for electrochemistry measurement. Cyclic voltammotry was performed to evaluate the electrode characteristics of diamond powder. The results shows that B-doped diamond powder electrode is electrochemically stable in the supporting electrolytes such as 0.1M KCl, 0.5M Na2SO4 and 0.1M H2SO4 over a wide potential range. The level of background current is very low. The electrode reaction is quasi-reversible in 0.5M Na2SO4 containing the ferricyanide-ferrocyanide redox couple.