Abstract: Firstly, hollow chestnut TiO₂ carrier was prepared by hydrothermal method with TiCl₄ as titanium source.Then, using PbI₂ and MAI as precursors, MAPbI₃ thin films were constructed on hollow chestnut TiO₂ by solution method to form hollow chestnut MAPbI₃/TiO₂ composite photocatalyst. Taking toluene as the target degradation material, the catalytic degradation performance of chestnut MAPbI₃/TiO₂ composite photocatalyst under visible light was investigated, and the energy level structure of the material was analyzed to reveal the degradation mechanism of the material. The results show that the composition and morphology of perovskite MAPbI₃ thin films are closely related to the feed ratio of PbI₂ and MAI. With the increase of feed ratio of PbI₂, the composition of the thin films changes from MAPbI₃ and MAI to pure MAPbI₃ and then to MAPbI₃ and PbI₂. The chestnut MAPbI₃/TiO₂ with matched energy level and special structure can not only reduce the recombination rate of photogenerated electrons and holes, but also effectively transfer the photogenerated electrons and holes to the conduction band of MAPbI₃ and TiO₂ valence band respectively, promoting the generation of active particles ·O₂⁻ and ·OH, so it has better performance in the degradation of toluene. Under the irradiation of visible light, the degradation rate of MAPbI₃/TiO₂ was up to 98% in 90 min.