In this study, a series of CuO@γ-Al₂O₃ particles were prepared using a facile impregnation–spray drying–calcination method. Fenton-like degradation of polyvinyl alcohol (PVA) over a wide pH range was investigated by focusing on the Cu²⁺/Cu⁺ redox cycle during the reaction. CuO@γ-Al₂O₃ with a suitable amount of CuO demonstrated high activity and stability for PVA mineralization. The reaction mechanism and degradation pathway of the CuO@γ-Al₂O₃/H₂O₂ system for PVA degradation were also discussed. Electron spin resistance tests demonstrated that ·OH, O₂·⁻, and ¹O₂ were the main contributors to PVA degradation. The CuO@γ-Al₂O₃/H₂O₂ system achieved an effective removal rate of PVA (92.65%) at the calcination temperature of 450 °C, γ-Al₂O₃:Cu(NO₃)₂·3H₂O mass ratio of 1:15, initial pH of 7, catalyst dosage of 2.5 g/L, reaction temperature of 70 °C, and H₂O₂ dosage of 10.5 g/L. Degradation tests of rhodamine-B and reactive red X-3B showed that the CuO@γ-Al₂O₃/H₂O₂ system has a certain applicability. These results provide new insights into the development of Cu metal oxides for the oxidative treatment of organic pollutants.