Ultrasonic sieving system consists of ultrasonic generator, energy converter and resonant ring. Ultrasonic generator produces high frequency oscillation and energy converter turns it into high-frequency sinusoidal longitudinal shock wave. This shock wave gets to resonant ring to make it resonate. Then resonant ring puts oscillation transmission to screen surface evenly. Materials on the surface will do low-frequency three dimensional vibration and ultrasonic vibration at the same time. This can prevent mesh clogging and improve yield and quality of screening.