The doping effect of a new dopant to BiOCl as photocatalyst is studied. SnS₂ as a narrow-band-gap semiconductor is used to tune the electronic and band structure of wide-band-gap BiOCl. BiOCl/SnS₂ hollow spheres are synthesized by a facile and economic one-pot hydrothermal method. The shell of the hollow spheres is composed by BiOCl and SnS₂, but the outermost layer is BiOCl. BiOCl/SnS₂ hollow spheres exhibit much higher photocatalytic activity than pure SnS₂ and BiOCl in the degradation of rhodamine-B under visible light and sun-light irradiation. The improvement is explained by the band structure tuning effect by SnS₂ and the morphological benefits of the hollow sphere structure.