On the basis of synthesizing the papers relating to seawater intrusion at home and abroad,this paper analyzes the study status,discusses the concept of seawater intrusion and thinks that the essence of seawater intrusion is the imbalance of water pressure due to excessive groundwater pumping.In addition,this paper analyzes the cause of formation of seawater intrusion,and thinks that dynamic water condition and hydrogeological conditions are necessary for seawater intrusion.Finally,the identification index,three-dimensional survey methods,prevention and controlling measures,and further study trend for seawater intrusion are also put forward.