This paper attempts to provide new insights into the engineering application of high-density polyethylene (HDPE) under impact load and the development of HDPE materials. For this purpose, an ANSYS/LS-DYNA numerical simulation was carried out for split-Hopkinson pressure bar (SHPB) impact compression test. A total of six working conditions (WCs) were arranged for the simulation. Comparing the stress waveforms of different specimens at the same impact velocity, it is concluded that the HDPE material has a certain energy dissipation effect under the impact load, but the effect cannot be effectively enhanced with the addition of HDPE sheets. The author also investigated the HDPE mechanical properties at different impact velocities of the bullet. The results show that the mechanical properties of HDPE material have a certain strain rate dependency under the impact load; the deformation of HDPE sheet became increasingly serious with theincrease of the impact velocity of the bullet.