Abstract: Tungsten substrate boron-doped diamond (W/BDD) film electrode was developed by chemical vapor deposition (CVD) method. The property of W/BDD film electrode was investigated by SEM and Raman. The electrochemical window and electrochemical property of W/BDD film electrode were measured in LiCl-KCl molten salt. The results show that the developed W/BDD film electrode has better microstructure. The electrochemical window of W/BDD film electrode is about 3.5 V(-2.5-1.0 V, vs Ag/AgCl). O^2- doesn’t react with carbon of boron-doped diamond film, and it is oxidated directly to oxygen atom. Morphology and microstructure of BDD film are not changed after long time electrolysis.