There may be several reasons for the pain in the small abdomen accompanied by low back pain: first, gynecological diseases, when the gynecology has pelvic inflammatory disease or pelvic effusion, there can be pain in the small abdomen accompanied by low back pain, which is often accompanied by waist pain and a feeling of swelling in the small abdomen, then the pelvic ultrasound should be performed for early diagnosis and treatment. Secondly, pelvic tumor, when pelvic tumor is serious, it can also appear pain in the small abdomen, accompanied by lumbar pain, then pelvic MRI should be performed for diagnosis and treatment. Thirdly, kidney and ureteral diseases, when kidney and ureteral stones are stuck in the ureteral stenosis when walking downward, low back pain, often colic, can be paroxysmal, accompanied by reflex pain in the small abdomen, then ultrasound and imaging of the urinary system should be performed for early diagnosis and treatment.