In order to investigate the erosion differences between SiO? and Al?O? particles on fan blades in high-bypass-ratio turbofan engines, the Euler–Lagrangian approach was used to track particle trajectories under typical sand and dust conditions defined by national standards. Particle trajectory, velocity, impact angle, and resulting erosion characteristics were compared. The results indicate that Al?O? particles exhibit more complex trajectories, with approximately 2% fewer entering the core flow path compared to SiO? particles. Their impacts are also more concentrated on the blade leading edge, and their rebound is more significant. In terms of erosion, Al?O? particles cause average and maximum erosion rates of 7.05×10?? kg/(m2·s) and 7.99×10?3 kg/(m2·s), respectively, which are 1.98- and 2.95-fold higher than those induced by SiO? particles. The impact angle of Al?O? is closer to the critical erosion angle of 30°, leading to more severe local material loss. Although both particle types show increased incident angles with blade height, SiO? consistently exhibits larger angles at the same height, resulting in a broader erosion distribution along the leading edge.