In order to obtain the theoretical model of the axial residual velocity of PELE (penetration with enhanced lateral efficiency projectile) under the condition of vertical penetration, the plane shock wave theory was used to analyze the mechanism of PELE vertical penetrating metal thin target. According to the penetration model of the flat head projectile, the energy loss during the penetration of PELE was divided into the following parts: the energy obtained by the annular plug block corresponded to the outer shell and the inner core, the increased internal energy of the outer casing and inner core, the shear energy dissipated in the outer casing. Based on the principle of energy conservation, the theoretical model of axial residual velocity after PELE vertical penetrating thin metal targets was obtained. To verify the rationality and accuracy of the theoretical model, the corresponding experiments were designed to verify the results. The results show that the calculated results coincide well with the experimental results under different conditions. Therefore, the theoretical model of axial residual velocity of PELE vertical penetrating thin target can provide guidance and reference for engineering application.