Pelvic effusion is a visible fluid that can be seen in the pelvic cavity and can be clarified by examining the uterine adnexal ultrasound or laparoscopy. Pelvic effusion is divided into physiological and pathological distinctions. In the case of physiological pelvic effusion, the amount of fluid is usually small and can be absorbed on its own. Common cases include leakage during follicle rupture during ovulation and fluid caused by poor gastrointestinal motility due to chronic constipation, which usually has no obvious symptoms and does not require special medication. Pathological pelvic fluid is mainly caused by inflammatory exudation such as pelvic inflammatory disease and adnexitis. If the amount of fluid is large and belongs to the acute phase of change, there may be fever, increased secretions, lower abdominal distension and pain, lumbago and other symptoms. If the amount of fluid accumulation is high, for example, reaching more than three centimeters, treatment with antibiotics needs to be intensified. If absorption is not obvious after treatment with medication, surgical aspiration of the fluid and cytological examination of ascites are required if necessary to exclude rare neoplastic diseases. In conclusion, if there are obvious symptoms such as lower abdominal distension and increased discharge, and if it is clear from ultrasound that pelvic fluid is present, early treatment is needed. Acute pelvic inflammatory disease is curable, but if it is not treated in a timely manner or if it is mismanaged, chronic inflammatory stimulation can easily develop and the effectiveness of treatment will be greatly reduced. Chronic pelvic inflammatory disease may cause painful swelling in the lower abdomen and lumbosacral area, abnormal discharge, etc., and recurrent episodes cannot be cured.