In order to investigate the ballistic performance, failure patterns and energy dissipation of aluminum alloy target plates against the impact of different strength and head shape projectiles, the three-dimensional models of 3 mm thick 6061-T651 aluminum alloy target plates impacted by lightweight-deformable projectiles of different materials were established by Abaqus finite element software, and the modified Johnson-Cook（MJC） constitutive model and the Lode-dependent modified Mhor-Coulomb（MMC） fracture criterion are used for numerical simulation. The results show that the corresponding ballistic limit velocity of the target plates are the highest when the low strength 6061-T651 aluminum alloy are used as the projectile material, and the ballistic limit velocity of the target plates decrease with the increase of the projectiles strength. The impact will cause a more complex failure patterns of the target plates when the projectiles strength is low, and at the same time, the plastic deformation of the projectiles head occur to different degree; the projectiles strength has a significant effect on the energy dissipation ability of the target plates. The ballistic limit velocity corresponding to the lightweight-deformable blunt-head projectiles are higher than that of the ogival-head projectiles.