Metallic sliver-doped mesoporous Al2O3 fibers (meso-Ag/Al2O3) that can harvest visible light to speed up solar water purification, were synthesized by one-pot hydrothermal method. Insightful analyses of XRD, XRF and XPS of meso-Ag/Al2O3 verified that metallic silver occupied interstitial positions of Al2O3 lattice forming interstitial solid solution. N-2 adsorption/desorption illustrated that meso-Ag/Al2O3 exhibited significantly increases in the specific surface area, pore volume and average pore diameter after doping with silver. The UV-Vis diffuse reflectance spectra and disinfection performance indicated that meso-Ag/Al2O3 can harvest visible light to promote the conversion of dioxygen to ROS for water disinfection compared with the widely used TiO2. With our approach, we achieved water disinfection of > 99.999% inactivation of bacteria in 120 min with a small amount of material (8 mg/L) under simulated visible light.