As the name implies, the ultrasound probe is placed inside the vagina for examination. The examination items are as follows: 1) observe changes in the endometrium, such as whether there is thickening, if thickening often indicates excessive menstruation; 2) observe endometrial polyps, uterine fibroids, endometrial cancer; 3) observe whether there is inflammation, ectopic pregnancy and occupying lesions in the fallopian tubes bilaterally, such as fallopian tube tumors; 4) observe whether there is fluid in the pelvic cavity and If the corresponding diseases are found, the corresponding treatment can be carried out. Yin ultrasound is only suitable for married women, unmarried women should avoid it as much as possible, and abdominal ultrasound can be used.