Sea water intrusion (SWI) is a characteristic problem of the resources and environment.It has been given much attention in many countries because the problem has brought about disaster along some coastal aresa in the world.Apart of SWI research outline in many countries in Europe, America, Asia, Australia and Africa having been presented in this paper, the authors lay stress on research contents, including three parts as follows. a)Territorial environment (geographic location, paleogeography and historical geogra-pahy, lithof acies and structure),b) The relationship between human activities and SWI(the development and utilization of water resources, the regulation of manland relationship in SWI regions). c)SWI mechanism (general considerations, the pathways, fresh-saline water interface and transition/miture zone). Last but not the least, some suggestions about future research direction have also been presented in this thesis.