Lying flat in the morning inside the small stomach hard may be due to abdominal muscles, abdominal muscle tension and other physiological factors or intestinal flatulence, constipation and other pathological factors. 1. developed abdominal muscles: if the patient often exercise, abdominal muscles are more developed, may appear in the morning lie down feeling hard inside the belly. 2. Muscle tension: due to excessive exercise of the abdominal muscles, or a long time in the state of exertion, resulting in the accumulation of lactic acid in the local muscles, thus appearing tension and stiffness, may also appear in the morning lying inside the small stomach hard situation. 3. Intestinal flatulence: due to indigestion or gastrointestinal diseases such as intestinal flatulence will also make the patient appear in the small stomach hard situation, usually accompanied by abdominal pain, increased exhaust and so on. 4. Constipation: If the patient is constipated and has not had a bowel movement for several days, there will also be hardness in the stomach in the morning lying down. The hardness of the stomach in the morning lying down, there may be other reasons such as bladder fullness, etc., it is recommended to go to the hospital in time to improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.