It is a common clinical symptom that can occur in various diseases of the urinary system, reproductive system and digestive system. 1. Cystitis, which is the main cause of vague pain in the small abdomen, is often accompanied by symptoms of frequent, urgent and painful urination. It is often accompanied by increased vaginal leucorrhea, yellowing and abnormal color, and may be accompanied by fever, loss of appetite and other systemic symptoms. 2. pelvic inflammatory disease is the most common gynecological disease that causes vague pain in the small abdomen. The diagnosis can be confirmed based on clinical symptoms, combined with routine laboratory tests of leucorrhea and gynecological ultrasonography. Once the diagnosis is clear, antibacterial drugs should be taken under the guidance of a doctor, combined with Chinese medicine to clear heat, detoxify and remove dampness for treatment.