One year old baby belly big bulging, may be a normal physiological phenomenon, but there may also be disease factors resulting in abnormal pathology. 1. physiological phenomenon: one year old baby belly big bulging, may and baby eating too full, or drink into too much water and so on related. Because more than one year old baby abdomen without too much muscle, abdominal wall is usually thin, when the diet, drink more water will produce the phenomenon of bulging stomach, is a normal phenomenon, generally do not need special medication. 2. pathological phenomenon: one year old baby belly bulging, may also be related to disease factors, if the baby belly bulging accompanied by repeated crying and nausea, vomiting and other symptoms, consider may be intestinal obstruction, megacolon and other diseases, the need for timely medical attention. One year old baby stomach bulging may also be related to other reasons, only based on the symptoms can not be accurately diagnosed, but also need to be combined with medical history, other test results to make an accurate diagnosis. Parents are advised to take their babies to the hospital to clarify the cause under the guidance of the doctor and actively treat them if necessary.