Color ultrasound means color ultrasound, the full name of color ultrasound is color Doppler flow imaging, the English abbreviation is CDFI. color ultrasound is not literally understood as all images are colored, that is pseudo-color, the image background can be shown in various colors, this is not the real meaning of color ultrasound, the real meaning of color ultrasound is not only has the advantages of two-dimensional ultrasound structure images, but also provides a rich information of hemodynamics. The true meaning of color ultrasound is that it has the advantage of two-dimensional ultrasound structural images and at the same time provides a wealth of information on hemodynamics. The ultrasound can be used in a wide range of clinical applications, including ultrasound examination of the circulatory system, digestive system, urinary system, male reproductive system, female reproductive system, superficial organs, blood vessels, lymphatic system, bones and joints, peripheral nerves, lungs, skull and brain, and other parts of the body, and can also be used to determine the functions of certain parts. It can be said that ultrasound can do everything, but some parts of the body have poor sensitivity to ultrasound.