The vibration mode of the radiation surface of transducer (or structure of supersaturated cavitation cloud in thin liquid) is investigated experimentally by high-speed photography.The classification of saturated, supersaturated and undersaturated cavitation clouds was proposed, and a comparison was made between saturated and Crocks supersaturated cavitation cloud structures in liquid thin layers.The characteristics and formation mechanism of supersaturated cavitation cloud structure were investigated.Based on the close correspondence and rapid response between the distribution of supersaturated cavitation clouds and vibration modes of radiation surface, a new approach is proposed to measure the vibration mode of transducer operating at high power and large amplitude Everything Else in real time.