Abstract: This study characterizes the interfacial structure of Cu-Ce/Al-Mg alloy composite strips under a range of annealing temperatures. The results indicate that the variety of intermetallic compound phases at the Cu-Al interface increases with higher annealing temperatures. No intermetallic compounds were formed after annealing for 1h at temperatures below 250 ℃. After annealing for 0.5 h at 350 ℃, a CuAl₂ layer formed on the aluminum side and a Cu₉Al₄ layer formed on the copper side of the interface. After annealing for 0.5 h at 450 ℃, a new intermetallic compound layer, CuAl, formed between the two layers of intermetallic compounds. When annealed at 350 ℃ and 450 ℃, extending the annealing time did not introduce new intermetallic compounds, but the thickness of the intermetallic compound layer increased. The Mg element in the Al-Mg alloy enhanced the thermodynamic stability of CuAl₂ during the annealing process, inhibiting its transformation into CuAl and reducing the growth rate of the CuAl layer.