High-resolution color Doppler ultrasonography PHILIPS-HD11, with advanced three-dimensional reconstruction and dynamic three-dimensional technology, is widely used in the diagnosis of obstetrical and gynecological diseases, and has become an important means of ultrasound examination of pelvic tumors and fetuses. The 3D ultrasound technology can overcome the weaknesses of 2D ultrasound spatial image deficiency and become an important auxiliary means of 2D ultrasound technology. The 3D ultrasound technology can not only provide the third plane image which is not available in 2D ultrasound, but also provide the stereoscopic image of the fetus in utero with photographic effect. The 3D ultrasound surface imaging can show the whole picture of the fetal facial organs and provide a three-dimensional image of the facial features. After 12 weeks of gestation, the whole body movements of the fetus can be observed, such as turning, stretching, head turning, etc. A variety of facial expressions can be recorded, such as frowning, smiling, yawning and swallowing, providing a lot of useful information for fetal medical research. In order to achieve satisfactory stereo image effect, the best time for 3D ultrasound examination is 28 – 32 weeks of pregnancy. For fetal surface masses, 3D imaging helps to accurately localize and determine the extent of malformations. It can also use the maximum transparent imaging mode to highlight the bone structure and obtain the effect similar to X-ray photos, which can clearly observe the structure, continuity, number, shape and correlation of fetal spine, ribs and limb bones, overcoming the shortcomings of 2D ultrasound which is difficult to clearly show the whole picture of fetal skeletal system in one plane, especially when the amniotic fluid is small and the fetal position is poor, it can more accurately diagnose the fetal skeletal It can diagnose abnormalities and malformations of the fetal skeletal system, especially when the amniotic fluid is low and the fetal position is poor. 3D ultrasound can also visualize placenta shape and position, determine placenta praevia and placenta morphology abnormalities, and also visualize umbilical cord entanglement and umbilical cord vascular structure. Ultrasound diagnosis of gynecological pelvic masses combined with 3D ultrasound technology can visualize papillary protrusions and structural features of the cystic wall within cystic adnexal masses, and can measure the volume of the tumor. Three-dimensional ultrasound has significant advantages over two-dimensional ultrasound in the observation of intrauterine occupying lesions such as endometrial polyps, uterine adhesions and endometrial cancer. Vaginal 3D ultrasound can be used to show pelvic adhesion zones and tubal effusion against the backdrop of pelvic fluid. 3D ultrasound can also visualize many kinds of uterine development abnormalities, such as double uterus, longitudinal uterus and bicornuate uterus.