The invention provides an ultrasonic cleaner and a substrate processing system and relates to the technical field of display. The ultrasonic cleaner is high in substrate blowing cleaning efficiency. Besides, when the ultrasonic cleaner is specifically applied to the substrate processing system, the surface cleanness degree of a substrate entering a processing device, and it is avoided that after the surface the substrate is processed, a large number of impurity residues are generated on the surface of the substrate. The ultrasonic cleaner comprises an air blowing unit, an ultrasonic oscillation generator and an air exhaust unit, wherein the air blowing unit is used for spraying airflow to the surface of an object to be cleaned, the ultrasonic oscillation generator is used for enabling the air sprayed out from the air blowing unit to generate oscillation, and the air exhaust unit is used for collecting the impurities blown out from the surface of the object to be cleaned.