Ultrasound imaging is a valuable application in modern medicine. The imaging generated by ultrasound wave could review the internal structure of human body. Thus, it can provide real lime and dynamic imaging of the internal organ and structure. The use of ultrasound imaging in obstetrics-gynecology, cardiology, internal medicine, for the scanning of abdominal internal organs, and injury of soft tissues has gradually gained important role in the diagnosis and treatment. As the trend of the use of ultrasound image is gradually prevailing, the research field in physical therapy also adapted this technology to broaden and deepen the research area. The main function of ultrasound imaging is to enhance the effect of therapeutic treatment through facilitation of the neuromuscular function and providing feedback to the therapist and patients. The purposes of this article are to review the history of the application of ultrasound imaging in medicine and, to introduce the basic principle of ultrasound wave and generation of imaging.