The effects of excess Mg, Si on the conductivity and mechanical properties of 6101 conducting wire were studied by the ways of conductivity measurement, tensile test, XRD and microstructure analysis .The results showed that, the alloys with more than 0.15% excess of Mg, after aging, one side, Mg would still exist in matrix and cause lattice distortion. On the other hand, the solubility of precipitates would be significantly reduced and easily turn to coarse phase causing by excess Mg. The changes in this two aspects restrict the improve of conductivity and mechanical properties; To the alloys with 0.13%, 0.05% excess of Si, after aging , the excess Si separate from the matrix, which decreases the degree of lattice distortion and promote the precipitation of β. In addition, excess Si reduces the bad effect of Fe by forming AlSiFe ternary phase. So excess Si does good for improving alloy’s conductivity and mechanical properties.