In order to improve the ammunition damage to light armor, a novel arc-cone liner which contains the low density filler was proposed. Numerical simulations by LS-DYNA were used to research the forming and penetration of the EFP. The influence of arc curvature radius on the forming of EFP was analyzed. The result shows that the liner can form a covered EFP with PELE structure. When the outer arc curvature radius of liner is 10~70 mm, the outer arc curvature radius of filler is 30~60mm, the inner arc curvature radius of filler is 47~59 mm, the inner arc curvature radius of liner is 45~55 mm, the EFP is formed with better performance. The optimized liner can create a lateral efficiency when it enters the target, and forming high-speed fragments in the target interior to form secondary damage when it penetrates the target.