This study investigated the improvement in the electrical conductivity and mechanical properties obtained by adjusting the amount of the Sr addition to the Al-Zn-Mg-Mn alloy. The addition of Sr formed an intermetallic compounds, and the volume fraction of the intermetallic compounds increased with increasing Sr content. As the amount of Sr added increased from 0 to 1.0 wt%, the electrical conductivity of the extruded alloy decreased to 48.9, 45.2 and 42.5% IACS. As the addition amount of Sr increased, the average grain size of the rolled alloy decreased to 55.5, 53.1 and 42.3 μm. And, the ultimate tensile strength increased to 195, 212 and 216 MPa.