The present study focused the effect of aluminium series backing layer on the ballistic resistance of bi-layer ceramic/metal target by means of three dimensional numerical simulation using ANSYS/AUTODYN explicit solver which is cable of modeling and solving the 3D explicit problems. The ceramic and metal layer of bi-layer target was alumina 95% and 1100-H12, 2024-T3, 6061, 7075 aluminium respectively and the impact velocity of ogive nose projectile of 4340 steel was 493, 820 and 1200 m/s. The strength and failure mode of alumina, and steel and aluminium under the projectile impact was computationally modelled by Johnson-Holmiquist (JH-2) model and Johnson-Cook (JC) model respectively. The results shows that ballistic resistance of bi-layer target significantly varied with the aluminium series. 7075 aluminium backing helped the bi-layer target to offer high resistance to the projectile penetration for all the impact velocities.