There are many reasons for a hard tummy, including physiological, such as obesity, overeating, full bladder, etc.; pathological common causes are gastrointestinal dysfunction, intestinal obstruction, tumors and other causes. 1. Physiological reasons: excessive obesity, overeating, full bladder, etc., will lead to a small stomach feel hard. 2. Gastrointestinal dysfunction: Gastrointestinal dysfunction will lead to a decline in the function of the stomach, intestines and other organs of the digestive tract, dysbiosis, gastrointestinal power is not enough, peristaltic frequency is reduced, the gas can not be emptied in a timely manner, in the local easy to form a stagnant, resulting in the symptoms of hardness in the lower abdomen. 3. Intestinal obstruction: the excretory function of the digestive tract is obstructed, and the gas and excretory material are easy to be deposited locally, resulting in the phenomenon of hardness of the lower abdomen. 4. Tumor: such as large posterior peritoneal tumor or female uterine adnexal large tumor, can appear small hard stomach. There are other causes of hard belly, so it is recommended to go to the hospital in time for examination and treatment after clarifying the cause of the disease.