Abstract: Magnesium matrix composite (Al₂O3f/ Mg-9Al-0.5Nd) was fabricated by pressure less infiltration . The effects of heat treatment on mechanical properties ，friction and wear properties of composite were studied . The morphology of worn surface and wear mechanism were explored by using SEM . The results showed that the hardness and the wear resistance of composite were greatly improved after heat treatment . For as cast composite the wear mechanism was abrasive wear and delamination wear . For heat treated composite , the ability to resist delamination wear was strengthened and the wear mechanism was characterized by abrasive wear