Abstract: To address the problem that existing slope scouring models fail to effectively capture the influence of particle shape on their motion states, the Lattice Boltzmann Method (LBM) and Discrete Element Method (DEM) were employed to simulate water flow and granular materials on a slope, respectively. The water impact force on particles was calculated based on momentum theorem. Factors such as Coulomb friction and cohesion of soil particle were considered in establishing the motion initiation criteria for particles. Particle motion and collisions were computed using Newton's second law, momentum conservation, and energy conservation principles. A random growth algorithm was introduced to generate the slope computational domain, and a slope scouring evolution model was finally established based on the coupled LBM and DEM. After verifying the reliability of this model, the effects of particle shape, gradation, and compactness on slope erosion were analyzed. Research results indicate that this model can effectively characterize phenomena such as large particle exposure, the formation of erosion pits, and the migration of small particles through the voids between large particles. Particles in the water inflow zone are mobilized first, while those near the bottom region remain stationary due to the low water flow velocity. Increased particle flatness can enhance slope erosion resistance. As the medium particles increase, small particles experience reduced hydrodynamic impact as they are shielded, and the interlocking between medium and large particles resists displacement under water scouring, thus enhancing the erosion resistance of slope. Small particles are prone to scouring-induced loss. An increase in their content raises compactness, thereby intensifying slope erosion. Conversely, a decrease in compactness from reduced small particles content results in the scouring-induced formation of internal voids.