Objective To study the effect of boron doping on the improvement of the resistivity of diamond film, and to prepare boron doped diamond film. Methods The hot-filament chemical vapor deposition (HFCVD) system was chosen for the preparation of Boron doped diamond (BDD) film on the Ti substrate, with the H2, CH4 and (CH3O)3B mixture as the reaction gas. SEM, EDX, Raman spectra, XRD and electrochemical workstation were used for the morphology and electrochemical detection of BDD film in different growth stage. Results The BDD film displayed uniform (111) crystal face, and obvious characteristic peaks of diamond atom and boron atom were found through Raman spectra. The background currents were low and the potential window was wider (3. 5 V). The COD degradation of phenol wastewater was remarkable. Conclusion The adsorption of organic pollutants was positively correlated with the roughness of the electrode surface. The laboratory prepared BDD / Ti electrode had smaller surface roughness, which was not favorable for the occurrence of hydrogen evolution and oxygen evolution, and could reduce the direct electrochemical oxidation, resulting in a wider potential window.