The heat-treatable, precipitation-hardening, aluminum alloys are of special interest for automobile where high strength and dent resistance are required, and for bumpers, where good strength and shock absorption are needed. In both cases, good formability is also an important requirement. The heat-treatable 6000-series Al-Mg-Si alloys have been the material of choice for automobile. Despite the high strengthening potential of Al-Mg-Si alloys, processing factors such as the artificial aging processes, as well as the duration of artificial aging, can seriously impede the strengthening process. The highest tensile strength of A6082 alloy was obtained when Mg/Si atomic ratio is set to 1.1 due to the biggest volume fraction of intermetallic compound containing Mg and Si. It was to determine how aging process affected the microstructure and mechanical properties of the A6082 alloy as different ratio between Mg and Si.