Abstract: In the simulation of concrete penetration, the mesh size has a direct effect on the calculation result. An example of a 57 mm caliber cuspidal warhead vertically penetrating a concrete plate (diameter 1.6 m, thickness 1 m) with a compacting velocity of 300 m/s was simulated by using non-linear dynamics analysis software AUTODYN-2D, The effects of different target mesh sizes on the penetration depth, overloading, and spalling size are studied. By analysising the simulation results, a proper range of mesh size with regard to this kind of problems is obtained.