Abstract: With Bi(NO₃)₃·5H₂O as bismuth source and KBr as bromine source, floriform photocatalyst of BiOBr was synthesized using the hydrothermal method to adjust pH of precursor solutions and characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), fourier transform infrared spectrometer(FTIR) and UV-vis diffuse reflectance spectroscopy (UV-vis). Meanwhile, the floriform photocatalyst was tested in photodegrading sugarcane molasses alcohol wastewater for effects of dosage of BiOBr, pH of the wastewater, aeration rate, dosage of KBrO₃ and intensity of illumination on decoloration rate of the wastewater. Results show that the hydrothermal products were all BiOBrs of the tetragonal crystal system with a band gap energy being 2.57-2.65 eV. The floriform BiOBr is capable of degrading effectively organic pollutants in sugarcane molasses alcohol wastewater, with a high decoloration rate. To treat 1∶30-diluted sugarcane molasses alcohol wastewater, the optimum running conditions were set as pH 0.11, BiOBr 3.0 g·L^-1, KBrO₃ 3.0 g·L^-1, aeration rate 120 L·h^-1(medium in rate), 180 min illumination under a 400 W metal halide lamp, 9 cm above the surface of the solution. In this case, the decoloration rate of the wastewater was 98.5% and the COD_Cr removal rate reached 51.8%. The photocatalysis process fits the first-order kinetic reaction.