For multilayer karst, the caves are rather small or the karst is developed along the bedding, and hence it is difficult to distinguish them directly from the cross-sectional view of the high-density resistivity method. By utilizing sounding curves extracted from high density electrical data and analyzing synthesized sounding curves as well as a cross-sectional view, different kinds of karst can be effectively distinguished. Engineering practice shows that the extraction of sounding curves from the data of high-density resistivity method for interpration can result in fairly good geological interpretation results.