Three-dimensional ultrasound is a three-dimensional dynamic display of color Doppler ultrasound diagnostic instrument, it is the same as the ordinary color ultrasound, color ultrasound is simply a high-definition black and white ultrasound coupled with color Doppler. Three-dimensional color ultrasound belongs to a kind of color ultrasound, three-dimensional color ultrasound is three-dimensional dynamic display. Color ultrasound used in obstetrics and gynecology is the main advantage of benign and malignant tumors identification and umbilical cord disease, fetal preterm heart disease and placental function assessment, for trophoblastic diseases have a better auxiliary diagnostic value, infertility, pelvic varicose veins through the observation of blood flow spectra, but also can be made under the diagnosis of black and white ultrasound difficult. The use of vaginal probe has certain advantages over abdominal exploration, and its superiority is mainly reflected in ① the sensitivity of uterine arteries, ovarian blood flow, high display rate. ②Shorten the examination time and obtain accurate Doppler spectrum. ③No need to fill the bladder. ④It is not disturbed by obesity, abdominal scars, or bowel insufflation. ⑤ Finding the pelvic organ tenderness site to determine whether there is adhesion in the pelvis with the help of the activity of the tip of the probe.