Abstract A novel Bi2S3/BiOCl/g-C3N4 nanocomposite was successfully synthesized and characterized for the first time, exhibiting strong visible-light absorption (up to 800 nm). Due to the synergistic effect derived from each component, photocatalytic activity of this composite under visible-light irradiation was greatly enhanced in the photodegradation of methyl orange (MO). Superoxide and holes were characterized as the primary reactive species generated in situ under the photoexcitation. Moreover, Bi2S3/BiOCl/g-C3N4 nanoplate also shows good reusability in aqueous solutions.