In present study, the aging behavior of the hot extruded semi-solid Mg-10Al-0.3Mn alloy was investigated. In order to obtain the extruded bar, we carried out the hot extrusion at 380°C with an extrusion ratio of 25 and ram speed of 2.4mms-1. Vickers hardness test, electrical conductivity measurements, scanning and transmission electron microscopy and tensile testing were performed to identify the aging behaviors and mechanical properties during the aging treatment. Observations of the aging behavior and results of the tensile tests after the T6 heat treatment at each aging temperature show that the optimum aging conditions was indicated by a hardness increment of 72% and a tensile strength of 340MPa in the extruded bar.