Ultrasonic dispersion is a powerful method of dispersing soil aggregates. Several procedures are described in the literature, which use absorbed ultrasonic energy as the main parameter for correlation with the process of soil dispersion. In the present work it is shown, that the dynamic of soil dispersion additionally depends on the magnitude of ultrasonic vibration. The vibration amplitude of the ultrasonic probe is an appropriate parameter in characterising the magnitude of loading, and a pro- cedure to measure this value is described. Soil particle distribution in dispersion experiments is correlated to both, the absorbed ultra- sonic energy per unit volume suspension and the amplitude of ultrasonic vibration.