<p>Iron oxide (Fe₂O₃) is widely used in biopharmaceuticals and environmental remediation for its stability and eco-friendliness, but limited by low specific surface area, agglomeration, and fast photogenerated charge recombination. Reduced graphene oxide (rGO) boosts its photocatalysis by promoting electron-hole separation, while Fe₂O₃ NPs further increase the composite’s specific surface area and active sites. In this study, a series of Fe₂O₃ NPs /rGO nanocomposites (FxGy) with different mass ratios were synthesized via a facile hydrothermal method. The microstructure, morphology, magnetic properties and photocatalytic degradation performance of the composites were systematically characterized by XRD, TEM, XPS, FT-IR, UV-Vis, N₂ adsorption-desorption, VSM and photocatalytic experiments with methylene blue (MB) as the target pollutant. Results showed that rGO effectively suppressed the agglomeration of Fe₂O₃ NPs, increased the specific surface area of the composite, and promoted the separation of photogenerated charges through strong interfacial coupling with Fe₂O₃ NPs. The F1G2 composite (Fe₂O₃ NPs: rGO = 1:2) exhibited the optimal photocatalytic performance, achieving 92.15% degradation of MB under visible light irradiation, with a degradation rate constant (7.40 × 10^− 3 min^− 1) 1.49–3.18 times higher than other composites. Additionally, the composite possessed superparamagnetic properties for rapid magnetic recovery and maintained good stability after four consecutive cycling tests. This work clarifies the structure-activity relationship of Fe₂O₃ NPs/rGO composites, providing experimental basis and technical insights for the practical application of Fe₂O₃-based photocatalytic materials in organic wastewater treatment and environmental remediation.</p>