Based on the photocatalytic activity and magnetic nature of magnetite and goethite, as well as the oxygen storage characteristic of cerianite, a magnetic ternary hybrid composite including cubic CeO2, cubic Fe3O4 and orthorhombic FeOOH, designated as Fe3O4/FeOOH/CeO2, was successfully synthesized with different Ce:Fe molar ratios using a simple hydrothermal route without subsequent calcination process, and employed as photocatalysts for the degradation of Acid Orange 7 (AO7) dye. The absorption range of light by the Fe3O4/FeOOH/CeO2 composites was broadened, and the intensity was enhanced. Furthermore, there existed a possibility of hybridization and doping among the three crystalline structures, with the elements Ce, Fe and O exhibiting a uniform distribution, significantly enhancing the photocatalytic efficiency of the Fe3O4/FeOOH/CeO2 composites in promoting the photodegradation of AO7. The magnetic response behaviors of hybrid composites synthesized with different Ce:Fe molar ratios were investigated. The adsorptive degradation of AO7 in darkness and the photocatalytic degradation of AO7 under UV light illumination were evaluated. Moreover, ten cycling runs of the photocatalytic degradation of AO7 under simulated UV illumination of Fe3O4/FeOOH/CeO2 synthesized with a Ce:Fe molar ratio of 1:15 were performed. The hybrid ternary composites were proved to have excellent magnetic sensitivity, exhibited outstanding photocatalytic activities and demonstrated remarkable stability. It is anticipated that magnetic Fe3O4/FeOOH/CeO2 ternary hybrid composites may have potential applications in the treatment of organic dye sewage.