To simulate the collision of a tungsten heavy alloy projectile with different velocities on the B4C ceramic target, an adaptive conversion model from Lagrangian elements to SPH particles is developed due to the limitations of the traditional finite element method (FEM) with the element erosion technique. By comparing the simulation results with experimental data and FEM simulation results, the accuracy and effectiveness of the model were validated. According to the damage morphological characteristics, the target damage was classified into the central crush area, cone cracks area, radial/circular area, and fragment falling area by analyzing the damage nephogram, and the formation causes of each area were discussed in detail. According to the simulation results, the impact process between the projectile and target is split into three stages: initial impact stage, erosion stage, and crack propagation stage, and the energy dissipation in each phase was computed and examined. Finally, the protection mechanism is summarized in detail. This study contributes to improve the protection mechanism system of B4C ceramic target.