The full name of B ultrasound is called B-type ultrasound diagnostic instrument, while the full name of color ultrasound is called color Doppler ultrasound diagnostic instrument, color ultrasound belongs to a type of diagnostic instrument of B ultrasound. Therefore, B-type ultrasound diagnostic instrument covers black and white B ultrasound diagnostic instrument and color Doppler ultrasound diagnostic instrument, and with the continuous development of ultrasound diagnostic instrument technology, color Doppler ultrasound diagnostic instrument is further divided into two-dimensional color Doppler ultrasound diagnostic instrument, three-dimensional color Doppler ultrasound diagnostic instrument and four-dimensional color Doppler ultrasound diagnostic instrument. Now the most widely used in clinical practice is two-dimensional color ultrasound, three-dimensional color ultrasound and four-dimensional color ultrasound are mostly used in large hospitals above the third grade.