Metal matrix composites(MMCs) represent a new generation of engineering materials in which a strong ceramic reinforcement is incorporation into a metal matrix to improve its properties including specific strength, specific stiffness, wear resistance, corrosion resistance, and high elastic modulus. In the present study A356 (Al-7%Si) aluminum alloy metal matrix composite MMCs) reinforced with different weight fractions of Al203 particles up to 25 wt% were fabricated by stir casting method. The effect of Al203 particle content on density, porosity, hardness, wear and corrosion behavior were investigated. The density measurements showed that the samples contained low porosity, which increased with increasing weight fraction of particles. The hardness increased with increasing weight fraction of particles. Sliding wear of MMCs is important wherever there is relative motion. This motion may be intentional, as in an internal combustion engine piston or automotive brake disc. The wear tests were carried out under the loads 20 and 40 N, with constant sliding speed lmls, and constant sliding distance 1240 m. The results shows that the wear resistance of the MMCs has increased with increasing weight fraction of particles. However, the wear resistance decreased with increasing in applied load.One of the main obstacles to use of MMCs is the influence of reinforcement on corrosion resistance. This is particularly important in aluminum alloy based composites, where a protective oxide film imparts corrosion resistance. The effect of weight fraction of Al203 on corrosion behavior of MMCs compared with its matrix alloy in 3.5% NaCI under stagnant, erosion , corrosive wear conditions using electrochemical potentiodynamic polarization test was investigated. The corrosion resistance of the matrix alloy in stagnant, immersion and corrosive wear conditions increases with addition of Alz03 up to 25 wt%. In erosion conditions the corrosion resistance was improved with adding Ah03 particles up to 20wt%. Although addition of 25 wt% Ah03 to the matrix alloy improved the corrosion resistant at stagnant conditions, this addition had bad effect in erosion corrosion conditions.