In the present study, the effect of the cold rolling process under the different reductions ratio (2.5, 5.0, and 7.5) were carried on AA 5456 Al-Mg alloy. During study, at the beginning and before starting the rolling process, the cast aluminum (AA5456) have been subjected to the heat treatments of homogenization at 450 °C for 18 hours and then annealing at a temperature 360 °C for 30 minutes for stress release and removing the effects side of casting. The homogenized Al-Mg alloy samples were undergone the plastic deformation process to assessments the microstructure and mechanical properties such Vickers hardness, Tensile strength as well erosion-corrosion property. The results showed that the homogenized rolled Al-Mg samples have the best value of both hardness and tensile strength. However, the homogenized Al-Mg underwent 7.5 % cold rolling process showed that significant increasing for Vickers hardness, tensile strength and resistance of erosion/corrosion in the impact angle 90°and 30° respectively.