In recent years, investigations of techniques for fabricating films having various functions have been actively conducted, and investigation taking in the powder which has function inside film attracts attention. In this study, we investigate the functionalization of aluminum plates. We attempted to fix titanium oxide (anatase-type) powder in crystalline boehmite film by the hydrothermal method. By the hydrothermal treatment for 30 minutes at 200°C, a 10 μm thick TiO2-boehmite composite film was formed on an aluminum plate. The composite film had superior adhesivity, hardness, and anticorrosive and photocatalytic activities. In particular, the TiO2-boehmite composite film showed higher photocatalytic activity than other crystalline boehmite films and SOL–GEL thin films. Furthermore the addition of aluminum nitrate increased the crystalline boehmite film thickness by three fold. Anatase-type TiO2 and AlO(OH) in the composite film were identified by XRD, and the surface of the film was observed to have globular [macroinstruction] and fibrous structures [microcosm] by SEM. In conclusion, the hydrothermal method was useful for improving the function of the aluminum plate: as well as for increasing film thickness and photocatalytic activity by the addition of aluminum nitrate.