Transabdominal ultrasonography is the most basic route of gynecologic ultrasonography and is widely available, but it is easily interfered by obesity, abdominal wall surgery scars, and abdominal gas, resulting in unclear image display and missed or misdiagnosis. Transabdominal ultrasonography requires the patient to drink more water and fill the bladder moderately before the examination, and the degree of bladder filling varies greatly among individuals, so it is often necessary to urinate a small amount due to excessive bladder filling or to continue to hold urine to complete the examination due to poor bladder filling, and sometimes even to repeat the examination several times, thus prolonging the consultation time. Compared with transabdominal ultrasound, transvaginal ultrasound does not require holding urine and is performed after urination before the examination. Because of the high resolution of the probe and the close proximity of the probe, the interference of intestinal gas and the attenuation of abdominal wall fat are avoided, so that the internal structure of the examined organs and lesions can be displayed more clearly and intuitively, and more diagnostic information can be obtained than in transabdominal examination. Despite the above-mentioned superiority of transvaginal ultrasound in gynecologic ultrasonography, it has some limitations: (1) It is not recommended for unmarried women, menstruating women, and those with severe vaginal inflammation. (2) For uterine fibroids and pelvic masses >6 cm in diameter, the extent of the lesion cannot be completely revealed, and combined transabdominal ultrasound is required in this case.