To study the incision characteristic of rods on thin target, the pertinent parameters were analyzed, a projection method about rods' incision length on thin target was constituted, and the penetration process of rods on plane target was simulated. It indicates that the incision characteristic of rods on thin target is influenced by rods' velocity, attack angle, incident, angle and surface angle. When the attack angle is more than 15°, the difference between rods' incision length got by projection method and. by simulation is less than 10%.