Abstract: The morphology and migration of the fresh water-salt water interface in coastal zones are of important significance in the studies of seawater intrusion in coastal aquifers. On the basis of comprehensive analyses of the relevant literatures of this fields, this paper introduces the advances in research on the fresh water-salt water interface at home and abroad in recent decades, analyzes the present situation of the research on the fresh water-salt water interface in coastal zones, and summarizes systematically the application and achievements of the analytic methods, numerical methods and experimental methods in the studies of the fresh water-salt water interface. The analytical methods can approximately determine the position and migration of the fresh water-salt water interface, the numerical methods are more accurate in describing the migration of the interface under the complex hydrogeological conditions and human factors, the experimental methods can directly observe the morphology and migration characteristics of the interface, and the electrical conductivity methods can effectively monitor the small changes in the interface caused by tidal effects. These obtained results enrich and develop the theory of the fresh water-saltwater interface. They are of important theoretical significance and practical value for the development and utilization of fresh groundwater resources and the environmental protection in coastal regions.