Bi₂Sn₂O₇–TiO₂ nanocomposites with different ratios of Bi₂Sn₂O₇ (BSO) and TiO₂ were prepared by combining a facile co-precipitation method with the aid of a template. X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy were employed to characterize the physicochemical properties of the as-prepared nanocomposites. The band gap energies of the nanocomposites were established by diffuse reflectance UV-Vis spectra. The specific surface area and average pore diameter of the nanoparticles were measured by an N₂ adsorption–desorption isotherm. Photocatalytic degradation of Rhodamine B dye molecules was also investigated in the visible region so as to explore the photocatalytic activity of the as-prepared nanocomposites. The results showed that the 10BSO–TiO₂ nanocomposites had a remarkably enhanced photocatalytic performance as compared with other samples including anatase TiO₂. It was also found that all BSO modified TiO₂ samples had a wider band gap energy than the pure BSO sample, but showed a higher photocatalytic activity than the pure BSO sample due to the photosensitization mechanism of the dye molecules.