Ag(2)O/TiO(2) heterostructure with high photocatalytic activity both in ultraviolet and visible-light region was synthesized via a simple and practical coprecipitation method by using surface-modified TiO(2) nanobelts as substrate materials. The as-prepared heterostructure composite included Ag(2)O nanoparticles assembled uniformly on the rough surface of TiO(2) nanobelts. Comparing with pure TiO(2) nanobelts and Ag(2)O nanoparticles, the composite photocatalyst with a wide weight ratio between TiO(2) and Ag(2)O exhibited enhanced photocatalytic activity under ultraviolet and visible light irradiation in the decomposition of methyl orange (MO) aqueous solution. On the basis of the characterization by X-ray diffraction, photoluminescence and UV-vis diffuse reflectance spectroscopies, two mechanisms were proposed to account for the photocatalytic activity of Ag(2)O/TiO(2) nanobelts' heterostructure.