Abstract: The erosion process produced by pre-mixed abrasive water jet was studied by the experiment and the simulation. The morphology of erosion damage was obtained from the experiment. An erosion model was established based on the Smoothed Particle Hydrodynamics coupling Finite Element Method. By using this model, the erosion process of the material was simulated and analyzed, and the mechanism of the damage morphology of the material was revealed. The results indicate that with the increase of erosion depth, the erosion kinetic energy of abrasive particles decreased, and the erosion angle increased. The erosion damage mode changed from micro-cutting and micro-ploughing to the impact deformation, and the damage morphology characteristics of erosion surface gradually deteriorated, which reflected as increasing declination angle and surface roughness. The damage morphologies of several metals were similar, while the material property had influence on the abrasive erosion process, resulting in the differences of the distributions and the declination angles of striations on the damage surfaces. The material damage morphology was determined by the movement characteristics of abrasive particles, so the quality of the eroded surface should be improved by the control of the movement features of abrasive particles. The study can provide a theoretical basis for the further research on the improvement of material quality of eroded surface.