AgCl/Ag/BiOCl with a concave-rhombicuboctahedron hierarchitecture with excellent photocatalytic activity is obtained via a facile vapor diffusion strategy at room temperature without template or any additives. The AgCl/Ag/BiOCl shows considerably higher photocatalytic activity than pure Ag/AgCl and BiOCl under visible light irradiation, in which the main active species are holes and Cl atoms. The possible charge transfer mechanism for the enhanced visible light photocatalytic activity is proposed. The slow reaction rate of the vapor diffusion process could produce the hierarchical structure AgCl/Ag/BiOCl which consists of cubic AgCl as the core and BiOCl nanosheets on the surface. The heterojunction between AgCl and BiOCl could effectively promote the interfacial charge transfer and decrease the combination of photoinduced electrons and holes, thus produce a large number of holes and enhance photocatalytic activity. Furthermore, strong adsorption activity of BiOCl nanosheets on the surface of AgCl/Ag/BiOCl also promotes the photocatalytic activity. Finally, low consumption of Ag and higher photocatalytic efficiency are both achieved in the AgCl/Ag/BiOCl heterojunction photocatalyst. This novel photocatalyst demonstrates potential application for organic pollutant elimination and proposes insight for designing highly efficient heterojunction photocatalysts.