Abstract: To investigate the erosion damage characteristics of composite insulators under wind-sand flow, this paper focused on the impact of sand particle shape characteristics on erosion damage. Firstly, based on research results of dust parameters in typical desert areas, a single-particle erosion dynamic model for sand morphology specific to Xinjiang Uygur Autonomous Region and Qinghai Province was established, allowing for the acquisition of stress response characteristics on the surface of the insulator's shed during particle impact. Subsequently, utilizing a wind-sand erosion simulation experimental platform in conjunction with characterization techniques for surface morphology, the microscopic morphological characteristics of the shed surfaces of composite insulators under different sandstorm environmental parameters were analyzed. Finally, through a correlation analysis between the stress distribution characteristics obtained via numerical calculations and the post-experimental microscopic morphology, the erosion damage characteristics of composite insulators were studied. The research results indicated that the lower the sphericity of the sand particles, the more pronounced the cutting damage to the sheds, whereas higher sphericity results in more significant compressive effects. As the erosion velocity increased, both the surface roughness of the sheds and the erosion wear rate exhibited nonlinear growth, leading to increased wear severity. The erosion angle was a key factor influencing the damage mechanism: between 10° and 30°, cutting wear predominated; at angles greater than 60°, deformation wear became the primary mechanism; and between 30° and 60°, both wear mechanisms could coexist. This study conducted a correlation analysis of stress response and micro-morphology regarding the erosion damage characteristics of composite insulators under wind-sand flow, providing a reference for the selection and optimization design of composite insulators for transmission lines in desert and gobi regions.