Abstract: BiOCl/coal gangue precursor was prepared by using sonochemical method with the raw materials of modified coal gangue, Bi(NO₃)·5H₂O and NH₄Cl. Bi₂S₃-BiOCl/coal gangue composite photocatalysts were in-situ synthesized through an anion exchange reaction between BiOCl/coal gangue precursor and thioacetamide (TAA). The crystal structure and morphology of Bi₂S₃-BiOCl/coal gangue composite photocatalysts were investigated by XRD and SEM. The photocatalytic activity of the as-prepared sample was evaluated by degradation of methyl orange under visible light. The results show that the Bi₂S₃-BiOCl/coal gangue composite photocatalysts exhibit an pronounced photocatalytic activity. The high photocatalytic activity could be mainly attributed to the formation of the heterostructures between Bi₂S₃ and BiOCl, which effectively separate the photoinduced electron-hole pairs and suppress their recombination.