Ag / Bi 4 Ti 3 O 12 heterostructure with high photocatalytic activity was synthesized via a simple and practical hydrothermal method by using Bi 4 Ti 3 O 12 nanobelts as substrate materials. The as-prepared Ag / Bi 4 Ti 3 O 12 heterostructure included Ag quantum dots assembling uniformly on the surface of Bi 4 Ti 3 O 12 nanobelts. Comparing with pure Bi 4 Ti 3 O 12 nanobelts, the composite photocatalyst exhibited enhanced photocatalytic activity under visible light irradiation in the decomposition of rhodamine B aqueous solution. The enhancement performance is believed to be induced by the intimate contact interface, where silver quantum dots serve as good electron acceptor for facilitating quick photoexcited electron transfer and thus decreasing electron-hole recombination. It was also found that the photodegradation of rhodamine B molecules is mainly attributed to the oxidation action of the generated [Formula: see text] radicals.