Ultrasonic waves travel into materials far away through with small energy. By using ultrasonic transducers and the electronic circuits, we can observe the various features of the ultrasonic wave propagation. The phenomena of the ultrasonic propagation relate closely to the characteristics of the materials, which constitute the medium of the ultrasonic wave propagation. The immersion ultrasonic sing-around method is a promising one for the purpose to characterize the properties of the solid materials, because the ultrasonic transducers do not contact the solid materials directly with this method. This is a small improvement for the investigation, but it is a very important one for the applications of the ultrasonic waves in the practical measurements, which require strongly the handiness, the reproducibility and the reliability. In the ultrasonic sing-around method, the received electrical signal by the receiving transducer triggers the next electrical transmitting pulse, which is applied to the transmitting transducer that transmits the ultrasonic wave into the medium. Then, the signal sings around the system by changing the feature as ultrasonic wave energy or as electric energy.