Layered protonated titanate nanosheets (LPTNs) loaded with silver nanoparticles are prepared by a simple one-pot hydrothermal route in silver-ammonia solution. The as-synthesized Ag-loaded LPTNs possess large specific surface area. The Ag nanoparticles are highly dispersed on the surface of the LPTNs. They have negligible effects on the crystal structure, crystallinity, and surface area of the LPTNs but result in considerable enhancement of visible-light absorption and in a red-shift of the band gap for the LPTNs. The Ag-loaded LPTNs show enhanced photocatalytic activity for both liquid- and gas-phase reactions under visible-light irradiation. Moreover, the photocatalytic activity first increases gradually with increasing Ag loading content, and then decreases after maximizing at an optimal Ag content. At the Ag loading content of 2.87 mol % and 1.57 mol %, the Ag-loaded LPTNs exhibit the highest visible-light photocatalytic activity for degradation of rhodamine B in water and mineralization of benzene in air, respectively. An alternative possible mechanism for the enhancement of the visible-light photocatalytic activity is also proposed.