A recyclable composite catalyst, Cu-FeO_x@AC, comprising Cu-Fe bimetallic oxides loaded on granular activated carbon, was developed for exploring novel algal treatment technology in eutrophic water. The catalyst was prepared using hydrothermal and high-temperature calcination methods and characterized via XRD, SEM, FTIR and XPS. Investigations into the effects of Cu-FeO_x loading ratio on AC, PMS quantity, initial pH, and different reaction systems were conducted to optimize algae removal. The study also explored the algae removal efficiency of the Cu-FeO_x@AC activated PMS system. Free radical shielding experiments and XPS analysis were carried out to explore the reaction mechanism of the Cu-FeO_x@AC activated PMS system. Results showed that at an initial pH of 6, initial algae concentration of 1.4×10⁹ per liter, catalyst dosage of 0.2 g/L, and PMS dosage of 0.5 g/L, the algae degradation rate reached 97.25% within 90 min. In this system, algal cells were adsorbed onto Cu-FeO_x@AC, facilitating valence conversion between Fe and Cu. The synergistic action of AC and the composite catalyst produced holes, ·O2-, ·OH, SO4-· and singlet oxygen, effectively removing algal cells.