Ballistic experiments of ceramic/mild steel composite target against 7.62mm armor-piercing projectile (APP) were designed and carried out. Limit velocities and the base radiuses of ceramic cone were obtained. The influence of projectiles initial velocity, the thickness of front and rear plate on the base radius of ceramic cone and the impact point to the resistant mechanism of target were analyzed. The results show that the ceramic cone can be separated into fragmentation and smash region, the base radius of which approximates the thickness of front plate plus projectile radius. The ballistic performance of composite target area is in a similar case except for an edge area (5mm to the edge of the target), in which the ballistic performance declines obviously. The edge area has to be discarded from the effective protective area.