Abstract: In this paper, high density electrical resistivity method was employed to study the salt-water intrusion transition zone combined with water quality survey sampling. Through an analysis of typical high density measurement section, 10 Ω;m is preliminary determined as the apparent resistivity indicator of the brackish water boundary in this area, and the location of brackish water zone, brackish water transition zone and fresh water zone in brackish and fresh water transition zone is preliminarily deduced. The result shows that the high density electrical resistivity method has the advantages of high efficiency, time saving and low cost, and can be used as an effective means to monitor the large range of salt water intrusion together with other methods.