In order to study the influence of V-shaped cavity degree(θ), length(L) and depth(H) on the damage efficiency of half-premade fragmented Penetrator with Enhanced Lateral Efficiency (HF-PELE), numerical simulations of HF-PELE penetrating 4340 steel were carried out by ANSYS/LS-DYNA. Based on the influence of V-shaped cavity degree on damage efficiency of HF-PELE, the optimized structure parameters were acquired by orthogonal test with θ, L and H as variables and maximum radial velocity(v_{r, max}) as the objective function: θ=40°, L=8mm, H =3.5mm and v_{r, max}=161.82 m·s^-1. Results indicate that the V-shaped cavity depth makes a big difference on the damage efficiency of PELE, the V-shaped cavity degree follows behind, and the V-shaped cavity length′s is minimum.