Abstract: Boron-doped diamond（BDD） thin film is a new electrode material that has received great attention recently owe to its possessing unique characteristics.Boron-doped diamond film on the heavily doped silicon substrate was prepared by the microwave plasma chemical vapor deposition.The electrochemical properties of BDD were characterized by resistivity measurement by 4-point probe method, SEM, Raman spectroscopy and electrochemistry working station.The resistivity of diamond films is 10^-2Ω·cm, Meanwhile, the quality of the diamond film was deteriorated with the increasing of boron doped.The electrochemical properties of the electrode were investigated using cyclic voltammetry, The results showed that Si/BDD electrode had a very wide potential window（2.8~3.2V）and very low background current（-3×10^-6~2×10^-6A）, comparing with Pt electrode（1.8V and-1×10-3~3×10^-4A）;and as electrode leader for BDD was jointed to the conducting substrate（high doped-Si）, more work area and lower cost of BDD could get.In electrolyte including Ferri/Ferrocyanide, the electrochemical reaction was carried out on the surface with good quasi-reversibility and excellent chemical stability.Studies of the oxidation of organic compounds showed that, comparing with Pt electrode, the diamond electrode could oxidate phenol, and the process of oxidation was very simple and complete.