Abstract: The penetration behavior and enhanced lateral efficiency of PELE filled core materials with density gradients against RHA plate was simulated by AUTODYN-3D code. The results show that the gradient-filled pattern of core materials has significant influence on the penetration behavior of PELE. For considerations of the higher lateral velocity in the front part of PELE,the core materials with declining shock impedance may generate a better enhanced lateral efficiency. In addition,numerical simulations also show that an exponential decline or a uniform length distribution of each core material part is much more useful to generate enhanced lateral efficiency.