For solving the problem that penetration rules study is absent beyond the muzzle velocity of the conventional artillery, a research method of high-velocity penetrators penetration into semi-infinite steel targets is proposed. Setting in the high speed launch platform, the velocity region is broadened on the basis of muzzle velocity region. The numerical simulation of different L/D ratio tungsten alloy penetrator incident penetrating into a 38CrMoAl semi-infinite steel target is performed using Autodyn code and Lagrange method. Based on the simulation consequence, the rule is analyzed. As a result, penetration depth and relative penetration depth are nonlinear increased with the penetration velocity increased is different clearly than it is in low velocity region. The total time of penetration in high velocity is shorter than it is in low velocity.