An effective protein-mediated route to decorate Ag nanoparticles (AgNPs) in TiO2 nanotube arrays (TiNT) is reported. The photocatalytic activity of the TiNT under UV irradiation causes the photoreduction of AgNPs to occur, and the biological template is decomposed simultaneously. Compared to undecorated samples, the AgNPs/TiNT samples under visible light display a much higher antibacterial activity against Escherichia coli.