Ultrasound imaging technology refers to the use of the physical characteristics of ultrasound, through high-tech electronic engineering technology of ultrasound transmission, reception, conversion and electronic computer rapid analysis, processing and visualization, so as to make a judgment on the physical characteristics of human soft tissue, morphological structure and functional status of a non-invasive examination. The normal human ear can receive sound waves in the frequency range of 16-20,000 hz, and sound waves higher than 20,000 hz are called ultrasound. The sound frequency used for ultrasound medical imaging is usually 3-7.5 million times per second (3mhz-7.5mhz). Ultrasound is a mechanical wave, its propagation is carried out through the mechanical vibration of particles in the medium, it is different from electromagnetic waves, in the vacuum can not be propagated, but in the human body complex medium propagation is better, while it is a linear propagation, so there is good directionality. Ultrasonic waves have reflection, refraction and scattering and other more unique some physical properties. When ultrasound in the medium of the propagation process, encounter two in the density and speed of sound are not the same medium, in its intersection that produces acoustic impedance, so that the reflection and refraction of sound waves and other phenomena. For example, a person shouting towards the mountain valley, the valley echo heard; and early radar scanning in the direction of a certain point to launch sound waves, encountering aircraft or other objects that produce the original direction of the reflected wave, received by the radar station can determine whether there are objects approaching and their distance and other information. These are the use of wave reflection principle. Similarly, the human body is a complex organic whole, the human body is distributed in many different tissues and organ structures, they have different acoustic impedance to the ultrasound, so that when the ultrasound through certain parts of the body and organs, in different tissues of large and small adjacent interfaces produce different reflections, refraction, scattering and diffraction, etc., this information is received by special instruments through electronic computers and other Medical personnel, after comparing the above ultrasonic information of the same part or organ of the normal human body with that of the suspect patient, can determine whether the suspect patient has abnormal lesions in the examined part or organ and make a diagnosis. Currently, ultrasound imaging technology has the advantages of real-time dynamics, high sensitivity, easy operation, non-invasive, no special contraindications, reproducibility, low cost and no radioactive damage. Thus, this diagnostic technique has become one of the most important tools in the examination, diagnosis and intervention of various clinical disciplines nowadays.