Tile ceramic composite armor has been lucubrated in the past 40 years. Ceramic can pro- vide the same protection as metal, but it has lighter weight than metal. Ceramic has excellent ability of resisting kinetic energy projectile, because it can transfer energy to a large range by its fragmented cone and has higher ability of eroding the projectile than metal. But the researches indicated the full potential of tile ceramic hard face has not been achieved because the significant interface between ceramic and metal has the unfavorable impedance effects and would induce tensile failure. FGM is a new type composite with continuous transition from ceramic to metal; it has no significant discrete materials interfaces between ceramic and metal. This paper deals with the impact response of Ceramic/FGM/Metal armor by numerical and theoretical methods. Firstly, the ability of TiB2/FGM/Metal armor resisting KE projectile is analyzed by Dytran FEM program. Tile comparison between TiB2/Metal armor and TiB2/FGM/Metal armor had been done; the results indicated that two main reasons result in the FGM armor is stronger than TiB2/Metal armor. One is FGM armor can make the best of the ceramic's hard face because of its continuous transition between ceramic and rnetal; another is the FGM armor can transfer energy to larger region than the ceramic/metal armor. Then, the penetration depth, residual velocity and mass of projectile have been analyzed by Dytran as FGM armor is attacked by 1000m/s projectile, three relations are attained: (I) the relation between the penetration depth and FGM's thickness; (2) the relation between tile residual velocity and FGM's thickness; (3) tile relation between the residual mass and FGM's thickness.