BiOCl/SnS2 core-shell heterojunction is prepared by a facile and economic hydrothermal method. The obtained BiOCl/SnS2 heterojunction displays high photocatalytic activity in the degradation of Rhodamine B (RhB). The high performance is explained by the fast separation of the photoinduced electron–hole pairs promoted by the heterojunction. The cycle life of the heterojunction is also improved compared with individual BiOCl or SnS2.