Pelvic fluid, a description of the image seen during ultrasound, belongs to a kind of ultrasound diagnosis, and can also be said to be a clinical symptom or sign of gynecological diseases, and is not an independent disease. There are physiologic pelvic fluid and pathologic pelvic fluid.1 Physiologic pelvic fluid, the diameter of the liquid dark area is not more than 1.0 cm in ultrasound examination, usually due to the increase of pelvic exudate during ovulation or menstruation, which does not need special treatment; 2 Pathologic pelvic fluid, the diameter of the liquid dark area is 1.0 cm and above, which can be seen in the pathology of pelvic inflammatory disease, endometriosis, and ectopic pregnancy, and so on. In the case of ectopic pregnancy, there will be pain and discomfort in the lumbosacral area and lower abdomen, and abnormal secretion in the vagina, etc., which need to be treated appropriately according to the specific cause.