Irritable bowel syndrome( IBS) is a commonly seen functional gastrointestinal disorder. Its main clinical manifestations were abdominal pain,abdominal distention and altered bowel habits. Currently,the pathogenesis of IBS has not been clarified. Studies showed that IBS was caused by many factors,including life style,gene polymorphism,food hypersensitivity,psychological factors,brain-gut axis abnormality and intestinal flora disorder. This article reviewed the advances in study on pathogenesis of IBS.