The mechanical properties of mechanically alloyed Al-4wt%Mg alloys dispersed with MgAl₂O₄dispersoilds at room and elevated temperatures were investigated. The powders in steady state during mechanical alloying consisted of Mg-supersatu rated Al solid solution and Al₄C₃which resulted from the reaction of Al with C in process control agent (methanol). The hot-extruded materials consisted of uniformly dispersed fine MgAl₂O₄, γ-Al₂O₃, Al₂O₃ and matrix with extremly fine substructure. Tensile specimens prepared from the extruded bars were tested at rowan temperature to 400℃ under different strain rates. The tensile strength of alloys at room temperature ranged from 500 to 594㎫. At elevated temperatures, the tensile strengths and elongations decreased with increasing temperature. Adding 3% MgAl₂O₄to Al-4wt%Mg increased the tensile strength of 50㎫ at rowan temperature and 20㎫ at 400℃.