The influences of rare earth elements(cerium and lanthanum) on the microstructure and phases of Al-3.0 wt%Mg alloys used for electromagnetic shielding wire were characterized by scanning electron microscopy(SEM), energy-dispersive spectroscopy(EDS), X-ray diffraction(XRD) and differential scanning calorimetry(DSC). The mechanical properties and electrical resistivity were also investigated. The results indicated that a certain content of rare earth could improve the purification of the aluminum molten, enhance the strength, and reduce the electrical resistivity of Al-3.0 wt%Mg alloys. The strength reached the top value when RE content was 0.3 wt% while the alloy with 0.2 wt% RE addition had the smallest electrical resistivity. The elongation varied little when RE addition was no more than 0.2 wt%. But the excessive addition of rare earth would be harmful to the microstructure and properties of Al-3.0 wt%Mg alloys. The influences of rare earth elements (cerium and lanthanum) on the microstructure and phases of Al-3.0 wt% Mg alloys used for electromagnetic shielding wire were characterized by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS) The results indicated that a certain content of rare earth could improve the purification of the aluminum molten, enhance the strength, and reduce the electrical resistivity of Al-3.0 wt% Mg alloys. The strength reached the top value when RE content was 0.3 wt% while the alloy with 0.2 wt% RE addition had the smallest electrical resistivity. The resulting varied little when when addition addition no more than 0.2 wt %. But the excessive addition of rare earth would be harmful to the microstructure and properties of Al-3.0 wt% Mg alloys.