The influences of Cu and Ce on the microstructures and mechanical properties of Al-7Si-0.35Mg alloys were investigated by using the control variables. The alloys underwent the same heat treatment: solution at 505 ℃ for ten hours. Then, the specimens were immediately cooled by water quenching. Finally, the samples were aged at 160 ℃ for 6 hours. The results have shown that Cu and Ce have a significant influence on the improvement of the tensile strength and elongation of the heat treated alloys. After heat treatment, the tensile strength of Al-7Si-0.35Mg alloy can be increased by more than 50% with 3.4%~4.0% Cu, when the Ce content is certain. The tensile strengths of Al-7Si-0.35Mg alloys with 3.6% ~3.8% Cu increase above 390 MPa. Ce has an effective modification on the morphology of eutectic silicon. When the Cu content is certain, the elongations of alloys can be improved from 4.2% to 7.4% with 0.15% Ce. Adding excess Cu and Ce to Al-7Si-0.35Mg alloys, Al9Ce2Cu5Si3 phases emerge. The results have illustrated that Al-7Si-0.35Mg alloys with 3.6% Cu and 0.15% Ce can attain good comprehensive tensile properties.