Doppler is generally a concept of acoustic effect, from the medical professional point of view, Doppler is one of the main functions of color ultrasound diagnostic equipment. In the color ultrasound examination, it is the use of the Doppler effect to check cardiovascular diseases, so the color ultrasound is also called color Doppler ultrasound diagnostic equipment. Color Doppler ultrasound diagnostic instrument in the clinic, in addition to the examination of general organs, such as the liver, gallbladder, pancreas, spleen, and genitourinary organs, is also mainly applied to heart diseases, such as congenital heart disease, rheumatic heart disease, and limb vascular diseases, such as arterial inflammation, atherosclerosis, arterial and venous embolism and other examinations.