Abstract: The motion characteristics of a vibrating screen directly affect screening efficiency and processing capacity. To investigate the motion patterns of an inclined box-type three-axis elliptical vibrating screen and its optimization mechanism for screening performance, this study established the motion equations of the screen's center of mass and a dynamic simulation model. The variations in amplitude, velocity, and acceleration of the center of mass over time were analyzed, along with the elliptical motion trajectory changes from the feed end to the discharge end. The results indicate that the displacement, velocity, and acceleration of the three-axis elliptical vibrating screen's center of mass exhibit periodic motion. From the feed end to the discharge end, the elliptical ratio continuously decreases while the direction angle increases. The major axis of the elliptical trajectory initially decreases and then increases, reaching its minimum at the center of mass, while the minor axis gradually expands. This demonstrates that the vibrating screen effectively propels materials toward the discharge end, preventing accumulation and subsequent screen end clogging.