In this study, Ag/Al(OH)(3) mesoporous nanocomposite film was fabricated for antibacterial agent. As a matrix, a mesoporous Al(OH)(3) layer was prepared by alkali surface modification of an Al substrate. Subsequently, mesoporous Al(OH)(3) matrix was immersed in a polyol solution for 4h at an elevated temperature to deposit silver nanoparticles (Ag NPs) by in situ dispersion. The Al(OH)(3) porous matrix had flaky crystals weaved and covered all substrate surface so that the specific surface area was considerably increased because of voids having several tens of nanometers between the flakes. After in situ dispersion of Ag NPs by polyol process, the Ag NPs were nucleated and grown at the surface of mesoporous Al(OH)(3) layer with tight binding. In antibacterial activity, Ag/Al(OH)(3) mesoporous nanocomposite film demonstrated an excellent bacterial growth inhibition property. It is believed that the Ag/Al(OH)(3) mesoporous nanocomposite film is suitable for the antibacterial agent in a wide variety of biomedical applications.