Although photocatalysis is frequently employed to remove various pollutants in water, it still suffers from low efficiency due to the rapid recombination of photogenerated electrons and holes. In this study, a red phosphorus/tin disulfide (RP/SnS₂) composite photocatalyst is fabricated by loading nano-sized RP on flower-like SnS₂ films with a facile hydrothermal method. It is noteworthy that the 2D heterojunction formed between SnS₂ and RP provided channels for the rapid transfer of photon-generated carriers and their effective separation. Furthermore, the separated electrons can react with absorbed O₂ for the generation of superoxide radicals (˙O₂⁻), thereby impacting the photocatalytic degradation oxidation reaction. The application of photocatalytic synchronous removal of Cr(VI) and RhB over RP/SnS₂ was implemented first. Compared with pristine SnS₂, the photocatalytic degradation activity of Cr(VI) and RhB over the RP/SnS₂ composite was significantly enhanced and the kinetic rate constant reached 8.2, which is 10.8 times that of pristine SnS₂. Moreover, the hybrid photocatalysts exhibited prominent reusability and stability. Therefore, a photocatalytic degradation mechanism and pathway of carriers are proposed in the study. Furthermore, it is considered that the present study is a promising method in the treatment of wastewater by photocatalysis.