Abstract: To study the influence of backplane strength on the anti-elastic properties of ceramic/fiber composite armor, a ballistic impact test of ceramic/fiber composite armor with different UHMWPE back plate angles was carried out by using 12.7 mm perforating projectiles (rigid brittle). The energy dissipation mechanism and anti-elastic energy of ceramic/fiber composite armor were analyzed by observing the macroscopic failure characteristics of the recovered projectile core, target ceramics and fiber backplane. The test results show that conical fracture is the main failure mode of ceramic panel, and the macroscopic cracks mainly include radial, annular and conical cracks. The deformation mode of the backplane is dynamic conical bulge and boundary fold, and its failure modes include shear failure and interlaminar stripping. The strength of the backplane has a great influence on the anti-elastic energy of ceramic/fiber composite target plate. With the stacking angle of UHMWPE back plate decreased, the strength of the backplane and the overall structural stiffness of ceramic/fiber target plate increase. The crushing effect of the target plate on the core becomes more obvious, and the mass of the maximum fragments in the residual core decreases after impact, while the number of small fragment increases. Penetrating the target plate, the residual penetration ability of the projectile fragments decreases, the anti-elastic energy of the target plate increases, the height of the backplane bulge decreases, and the angle formed by the conical bulge increases. The failure mode of fiber laminates changes from shear failure to interlaminar stripping.