In this paper, CeO2/Fe3O4 nanocomposites as magnetically recoverable photocatalysts were synthesized via Fe3O4 covering the surface of CeO2 by a hydrothermal method, to form a flower-shaped photon-Fenton catalyst with a larger specific surface area. The composition, morphology and physicochemical properties of the materials were characterized. It was found that the mesoporous CeO2/Fe3O4 composite material as an adsorbent, photocatalytic and Fenton-like catalyst largely overcomes the limitations of the oxidation properties of CeO2 and has multiple effects on the removal of Congo red (CR). The superior adsorption capacity of mesoporous materials is attributed to the abundant oxygen vacancies on the surface of CeO2 and the high specific surface area. In the photo-Fenton reaction process, photocatalysis and Fenton reaction have a synergistic effect, which greatly improves the photocatalytic performance of CeO2/Fe3O4 and has a strong photodegradation ability to pollutants. Moreover, the degradation of CR was enhanced in the presence of hydrogen peroxide (H2O2) by the synergistic effect of Fe and Ce valence changes. Flower-shaped photon-Fenton catalyst CeO2/Fe3O4 has a good degradation effect on high concentration CR. Under the optimal conditions of pH 4, H2O2 3.75 mL/L, and catalyst 1.0 g/L, the removal rate of CR 1000 mg/L can reach 82% in 120 min. After the degradation reaction, the CeO2/Fe3O4 catalyst was recovered from the reaction mixture using an external magnet and successively used for five consecutive cycles with a considerable catalytic activity which is comparable to the first time was obtained.