///Seawater intrusion is one of the environmental problems in coastal regions. Dalian, an important coastal and industrial city is located at south end of Liaodong peninsula in the North China, and is geographically surrounded by Bohai Sea and Huanghai Sea in the west, south, and east. The city is critically short in water resources. Seawater intrusion had been found since the groundwater was over withdrawn from the coastal karst and fractured aquifers in the 70’s of last century. Industry and agriculture, ecoenvironment and physical health of local people was to different extent affected by seawater intrusion. Nowadays, the problem had been controlled. The prevention and recovery measures of seawater intrusion were brought forward according to local conditions.