As an alternative for perfluorooctane sulfonic acid (PFOS), sodium p-perfluorononyloxybenzene sulfonate (OBS) has been widely used in petroleum, fire-fighting materials, and other industries. In order to efficiently and economically remove OBS contaminations from water bodies, in this study, a ternary heterojunction was constructed by coupling BiOBr and BiOI@Bi 5 O 7 I for improving the redox capacity and carrier separation ability of the material and investigating the effect of the doping ratios of BiOBr and BiOI@ Bi 5 O 7 I on the performance of the catalysts. Furthermore, the effects on the degradation of OBS were also explored by adjusting different catalyst doping ratios, OBS concentrations, catalyst amounts, and pH values. It was observed that when the concentration of OBS was 50 mg/L, the amount of catalyst used was 0.5 g/L, and the pH was not changed. The application of BiOBr/BiOI@ Bi 5 O 7 I consisting of 25% BiOBr and 75% BiOI@ Bi 5 O 7 I showed excellent stability and adsorption degradation performance for OBS, and almost all of the OBS in the aqueous solution could be removed. The removal rate of OBS by BiOBr/BiOI@ Bi 5 O 7 I was more than 20% higher than that of OBS by BiOI@Bi 5 O 7 I and BiOBr when the OBS concentration was 100 mg/L. In addition, the reaction rate constants of BiOBr/BiOI@ Bi 5 O 7 I were 2.4 and 10.8 times higher than those of BiOI@ Bi 5 O 7 I and BiOBr, respectively. Therefore, the BiOBr/BiOI@ Bi 5 O 7 I ternary heterojunction can be a novel type of heterojunction for the efficient degradation of OBS in water bodies.