<p>The effect of rare earth cerium (Ce) on the microstructure and phase structure of an aluminum alloy was systematically investigated by optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM), and X-ray diffractometer (XRD). Additionally, the electrical conductivity and mechanical properties were thoroughly evaluated to explore the comprehensive effects of Ce addition. The introduction of Ce changes the existence form of impurity elements such as Fe and Si in the aluminum matrix and promotes grain refinement of the alloy. The results showed that rod-like Al₆Fe and Al₃FeSi₂ phases were observed at the grain boundaries of the Al-0.2Er alloy. And for the Al-0.2Er-0.2Ce alloy, Al₃Er, Al₁₁Ce₃ and AlFe(Er, O)-x (impurity) phases were distributed in the alloy. Nanoscale Al₃Er and Al₁₁Ce₃ phases contributed to strength enhancement, while the complex AlFe(Er,O)-x(impurity) phase further purified the matrix. The Al-0.2Er-0.2Ce alloy exhibited an electrical conductivity of 63.9 %IACS, a tensile strength of 127&#xa0;MPa, and an elongation of 12.4%, representing increases of 0.6 %IACS, 28&#xa0;MPa, and 2.2% compared to the Al-0.2Er alloy. These results demonstrate that Ce addition effectively improves the comprehensive properties of aluminum alloys. This study provides a theoretical foundation for developing high-strength and high-conductivity aluminum alloys.</p>