A carrier and a catalyst, i.e., porous carbon fiber prepared by the etching template method and ferroferric oxide (Fe₃O₄), respectively, were uniformly mixed and vacuum-filtered to prepare a photothermal membrane (PTM) with interfacial heating and photo-Fenton catalytic properties. The material was characterized using X-ray diffractometer, scanning electron microscope, specific surface-area and porosity tester, and ultraviolet-visible spectrometer. Additionally, the effects of pH, hydrogen peroxide dosage, and solar radiation density on the degradation efficiency of the material were studied. The experimental results show that the degradation rate of RhB reached 100% after 80 min of reaction when the initial concentration of RhB was 10 mg/L, the pH value was 5,the dosage amount of H₂O₂ was 300 μL, and the solar radiation density was 3 kW/m². The catalytic efficiency of the photothermal membrane was 92% after 10 experimental cycles, indicating the high stability of the PTM.