<p>The development of efficient and economical photocatalysts is the focus of achieving sustainable remediation of water pollution. However, slow photogenerated carrier transfer and insufficient catalytic sites are the main reasons affecting photocatalytic applications. Herein, we developed flake-octahedral BiOBr/MIL-101(Fe) heterojunction catalysts through a facile solvothermal strategy for the degradation of pollutants under visible light irradiation. Scanning electron microscope, X-ray photoelectron spectrometer, Fourier infrared spectrometer, and X-ray diffraction analysis characterizations proved the successful synthesis of flake-octahedral BiOBr/MIL-101(Fe) heterojunction. Absorption spectra and Brunauer–Emmett–Teller analyses showed that the BiOBr/MIL-101(Fe) composites with an atomic percentage of Fe of 9.1 (denoted as BiOBr/MIL^III) had the optimal light absorption and the largest specific surface area. The BiOBr/MIL^III achieved a remarkable Rhodamine B (Rh B) degradation efficiency of 94.5% within 60&#xa0;min, with an apparent rate constant (<i>k</i>) of 0.03540&#xa0;min⁻¹, demonstrating excellent visible light-driven photocatalytic activity. Photocatalytic mechanistic studies showed that the solvothermal-induced flake-octahedral BiOBr/MIL-101(Fe)^III heterojunction promotes the formation of Z-scheme, which significantly enhances the carrier separation efficiency and accelerates the rapid generation of reactive radicals ^·O₂⁻ and h⁺. This work provides a feasible strategy for the construction of flake-octahedral inorganic-MIL photocatalysts with excellent photocatalytic performance.</p>