Gastroesophageal reflux disease (GERD) is a common recurrent disease and the treatment of GERD is challenging. Chronic heartburn and/or reflux symptoms seriously affect the quality of daily life of patients. Studies have shown that GERD is closely associated with the impairment of anti-reflux barrier of the esophagus,of which mucin (MUC) is the main component. The role of MUC in the pathogenesis of GERD and influencing factors were reviewed in this article.