Obsessive-compulsive disorder (OCD) is a common mental disorder with obsessions and compulsions as its main clinical manifestations. In recent years, many researches using functional magnetic resonance imaging have concentrated on the relationship between obsessive-compulsive symptoms and large-scale brain networks. Combined with the triple network model hypothesis, this article reviews the current research status of brain network mechanisms corresponding to obsessive-compulsive symptoms by focusing on functional abnormalities of Default Network, Salience Network and Frontoparietal Network involved in the pathophysiological process of OCD, with a view to providing new clues for the early recognition and intervention of OCD.