Color ultrasound is simply a high-definition black-and-white ultrasound plus color Doppler, first of all, ultrasound frequency shift diagnostic method, that is, D ultrasound, this method applies the principle of the Doppler effect, when there is a relative motion between the source of the sound and the receiving body (i.e., the probe and the reflector), the frequency of the echo is changed, such frequency change is called the shift, D ultrasound, including pulsed Doppler, continuous Doppler and color Doppler blood flow images. Doppler, continuous Doppler, and color Doppler flow images. Currently, the direction of development of ultrasound in the medical field is color ultrasound.