Abstract: Efficient and fine crushing of lunar regolith particles is a crucial prerequisite for in-situ resource utilization. Owing to the high-hardness components and agglomerated structure of lunar regolith, traditional crushing equipment cannot meet the demands of efficient and fine particle crushing. To address this issue, a composite crushing method combining ultrasonic vibration with rotational shear is proposed in this study. A spiral-groove ultrasonic longitudinal-torsional horn is designed, and a small-scale crushing device integrating ultrasonic, pressure, and rotational mechanisms is developed. Crushing simulations based on the EDEM discrete element software and experiments are conducted, and the cooperative crushing mechanism involving differential damage and disintegration of particles with different sizes is revealed. The experimental results show that the crushing efficiency of the device is negatively correlated with the particle size. After 180 s crushing time, the crushing rates of particles with sizes of 0.12～0.85 mm, 1～3 mm reach 90% and 70%, respectively. This study provides a low-power, small-volume, and high-adaptability crushing scheme for the development of in-situ crushing equipment for lunar regolith particles, which holds important reference value for promoting the efficient in-situ processing of extraterrestrial celestial resources and the construction of lunar bases.