The high intensity focused ultrasound (HIFU) surgery technique is an important application of medical ultrasound. As the ultrasound transducer is placed out of the body, HIFU technique belongs to non-invasive extracorporeal therapeutic technology. It is able to focus ultrasound energy deep into the body, forming destruction in pathologic change tissues and coagulating them without any damages to tissues out of the focus. The development of ultrasound transducer is the key technology of HIFU.