Thin extremities and large stomach are commonly seen in cirrhosis compensatory stage, gastrointestinal and digestive tract tumors, and malnutrition diseases. Obese people are prone to the phenomenon of thin limbs and large stomach, indicating that the patient has particularly thick fat below the skin of the stomach and more fat in the abdominal wall, so the phenomenon of thin limbs and large stomach appears, and the symptoms can be improved by weight loss if necessary. It can also be considered to be caused by other diseases, commonly post-hepatitis cirrhosis, which is prone to hypoproteinemia during decompensation, so ascites will appear. Although the limbs look thinner, the stomach will look bigger because of the water inside the abdomen. Further examination at the hospital is needed and treatment by diuretic and albumin supplementation. The gastrointestinal tract or digestive tract is prone to various tumors, such as malignant tumors that grow faster in the middle and late stages, and the abdomen will gradually increase in size and cause ascites manifestations, which need to be surgically removed in the hospital. Nutritional diseases such as tuberculosis, which can lead to a large amount of ascites in patients, can be diagnosed by abdominal ultrasound in hospitals and require anti-tuberculosis treatment, such as isoniazid plus rifampicin, which requires more than 1 year of treatment.