For the principle of ultrasonic cleaning machine, the high-frequency oscillation signal sent by the ultrasonic generator is converted into high-frequency mechanical oscillation through the transducer and propagated to the medium-cleaning solvent. The ultrasonic wave radiates forward in the cleaning solution, which makes the liquid flow and produces tens of thousands of 50-500 diameters μ M tiny bubbles, tiny bubbles existing in liquid vibrate under the action of sound field. These bubbles form and grow in the negative pressure zone of ultrasonic longitudinal propagation, while in the positive pressure zone, when the sound pressure reaches a certain value, the bubbles rapidly increase and then suddenly close. The shock wave will be generated when the bubble closes, and thousands of atmospheric pressure will be generated around it, which will destroy the insoluble dirt and disperse them in the cleaning fluid. When the group particles are wrapped in oil and adhere to the surface of the cleaning part, the oil will be emulsified and the solid particles will be separated, thus achieving the purpose of cleaning the cleaning part. In this process called "cavitation" effect, the bubble closure can form a high temperature of several hundred degrees and an instantaneous high pressure of more than 1000 air pressures.