Abstract: To investigate the influence of ultrasonic vibration on the distribution of the Nd-rich phase in hot-deformed Nd-Fe-B magnets, MQU-F type melt-spun powders were used to prepare hot-deformed Nd-Fe-B magnets through hot pressing and hot deformation processes, with ultrasonic vibration applied during the hot deformation stage. The deformation stress during the conventional and ultrasonic-assisted hot deformation processes of the magnets was analyzed using Abaqus software. The distribution and composition of the Nd-rich phase were examined through SEM and EDS imaging, while the magnetic properties at the center and edges of the magnets were detected using the MPMS3 magnetic property measurement system.The results indicate that after applying ultrasonic vibration, the deformation stress of the magnet is reduced due to the acoustic softening effect, leading to a 22.3% decrease in the compressive stress on the melt-spun ribbons and a significant reduction in the extrusion of the Nd-rich phase from within the ribbons. Consequently, the diffusion channels of the Nd-rich phase between adjacent melt-spun ribbons and neighboring grains are widened.Influenced by the proportion of the Nd-rich phase region and the diffusion channels between adjacent grains, the aggregation ?region of the Nd-rich phase within the melt-spun ribbons changes. Under acoustic streaming, the Nd-rich phase in hot-deformed Nd-Fe-B is subjected to an equivalent force from acoustic pressure, causing its concentrated distribution region to diffuse from the central section of the magnet toward the lower end face. When the ultrasonic power ranges from 0 to 47 W?cm-2, higher ultrasonic power results in greater equivalent force from acoustic pressure, making the Nd-rich phase more prone to accumulation at the lower end face of the magnet. Due to the widening of the diffusion channels of the Nd-rich phase between adjacent melt-spun ribbons, the Nd-rich phase is more uniformly distributed along the radial direction of the magnet, resulting in a significant enhancement of the coercivity, with increases of 25.4% and 30.9% observed at the center and edge of the hot-deformed magnet.