Barium titanate films were deposited by electrochemical oxidation during which 0.5 M barium acetate was used as the electrolyte over a wide electrolytic voltage range of 3-90 V The microstructure of the films was controlled primarily by the applied electrolytic voltage. The structure-sensitive voltage ranges were first determined by the voltage scanning electrolysis method; the films were then prepared to the preset voltages by the potentiodynamic method. The BaTiO3 thin films possessed uniformly distributed spherical-like small particles at voltages under 30 V because of the dissolution and crystallization mechanism. At voltages from 45 to 60 V, X-ray diffraction results showed favorable generation of the rutile TiO2 phase. The formation of crater-shaped and large-grained BaTiO3 films at voltages above 60 V may be attributed to the anodic spark deposition mechanism.