To enhance the damage effectiveness of anti-light armor target ammunition, a kind of variational-wall-thickness arc-cone liner with low-density loading material was proposed. The influence law of each cone angle on explosively formed projectiles (EFP) forming and the penetration effect of EFP on target plate were analyzed by finite element software LS-DYNA. The curve of EFP forming parameters with each cone angle was obtained by fitting. Results show that when the inner cone angle α₁ of liner takes 166°-170.2°, the inner cone angle α₂ of filler takes 160°-166°, the outer cone angle α₃ of filler takes 140°-152°, the outer cone angle α₄ of liner takes 132°-140°, the EFP forming speed is fast and forming effect is good. The α₃ has the greatest influence on the forming speed, length and radial dimension of EFP, and the α₁ has the greatest influence on the center thickness of EFP. Based on the research results, the structure of the liner was optimized. The optimized liner can form an EFP with distinct penetrator with enhanced lateral efficiency(PELE) effect, which expands the hole when penetrating the target plate and forms some high-speed fragments in the target interior to cause secondary damage after penetrating the target plate.