The role of ultrasound is mainly three major aspects of the application of ultrasound diagnostic technology, ultrasound processing, basic research. Ultrasound is the mechanical vibration wave of the object, belongs to a kind of sound wave, has an important role in our daily life, ultrasound involves a lot of fields, ultrasound sound wave frequency is higher than 20,000 hertz, it is more penetrating, better direction. 1. The application of ultrasonic diagnostic technology: ultrasound can be used to detect the thickness of the material, material distance and ultrasonic imaging technology. At present, the clinical application of ultrasound instrument is the use of ultrasound imaging technology, ultrasound through the transducer conversion of the scanned object imaging to the fluorescent screen, to achieve the role of object detection. Ultrasound instrument for its convenience, speed, economy, safety, accuracy and other advantages are widely used in medicine, used to check the human body and the animal body substantial organs whether there are abnormalities. In recent years, clinical doctors in the ultrasound guidance, can do a variety of biopsy, puncture, imaging or interventional therapy and so on. 2. Ultrasonic treatment: ultrasonic treatment is a use of ultrasound mechanical, cavitation and its thermal and chemical effects, to achieve ultrasonic welding, crushing objects, dust removal and other effects. 3. Basic research: through the study of ultrasound, to clarify how ultrasound is generated, propagation and reception. Thus, the research of ultrasonic device generator, such as the steam whistle. Through the study of ultrasound to produce sound energy converter.