BaTiO3/TiO2 heterostructure nanotube arrays were fabricated by in situ hydrothermal method using TiO2 nanotubes as both template and reactant. The BaTiO3/TiO2 heterostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. Compared with pure TiO2 nanotube arrays, the BaTiO3/TiO2 heterostructures exhibited enhanced photocurrent under UV light irradiation. The electrochemical impedance spectra (EIS) showed that the impedance arc radius of BaTiO3/TiO2 heterostructures was much smaller, indicating an improved charge carrier separation ability was achieved. In addition, the BaTiO3/TiO2 heterostructure nanotube arrays displayed a higher photocatalytic activity for methylene blue degradation.