Abstract: An analysis method regarding the crater diameter of tungsten sphere impacting the low carbon steel plate at high velocity was studied. Some experiments were performed by using 12.7mm smooth bore ballistic gun and 57.5mm/14.5mm two-stage light-gas gun, loading the <i<Φ</i<6mm and <i<Φ</i<7mm tungsten spheres to impact different thickness Q235 steel plates at 600~2400m/s. The projectile-target impacting process was analyzed according to experiment result; the edge of impact craters was observed with the scanning electron microscopy(SEM). Results show that when impacting at 1000m/s, the destruction of target is mainly fracture failure; when impacting at 1500m/s, the destruction is mainly plastic flow. Based on the experiment result, the tungsten sphere plastic deformation, the target dynamic yield and plastic flow, the crater diameter calculation model of tungsten sphere impacting low carbon steel at high velocity are established; the difference between the calculated result and the experiment data is less than 12%.