In the process of coal slime treatment, the adhesion and agglomeration between coal slime particles considerably hinder the effective contact between coal slime particles and chemicals, which leads to a series of problems such as the reduction of sorting efficiency and product quality. In order to deeply explore the influence of ultrasonic assisted dispersion of coal slime particles, this study measured the particle size change of coal slime in different ultrasonic power and different treatment time. At the same time, by using COMSOL Multiphysics simulation software to build an acoustic-fluid coupling model, combined with the theory of acoustic radiation force under the condition of large amplitude sound source, the acoustic flow phenomenon generated by high-power ultrasound with a frequency of 20 kHz in the material cavity was simulated and analyzed, and the change law of acoustic flow velocity under different ultrasonic powers was obtained. The internal correlation between the velocity of acoustic flow and the dispersion of slime particles was revealed. The experimental results show that ultrasound has a significant effect on the dispersion of slime particles, and with the increase of ultrasonic power and the extension of treatment time, the dispersion effect of slime particles is more and more obvious. Under 600 W ultrasonic power and 5 minutes of treatment, the proportion of particles in the 0.075 – 0.15 mm size range increased by 10.98%.