Since 1981,experimental recearch work of applying IP method to large-areauuderground water survey has been conducted in different geomorphologicalunits and diverse stratigraphic and lithologic areas such as loess land ofLingbao County, hilly country of Xinan County and plain area of Xiuwu County,with a total surveying area of 1933.8km². This paper outlines the basic techni-ques of carrying out large-area survey, draws contour maps of ρ_s、D、 η_s、J according to large quantities of measured data, and, on such a basis, makescorresponding inferred geological diagrams including sand-gravel confined water-bearing bed of deep-buried Lower Pleistocene (Q) fluviolacustrine facies in loess land (Ling-Shan faulted basin) of Lingbao County, the Nangang undergroundreservoir in hilly country of Xinan County and the Qinhe old channel. Drillinghas demonstrated fine geological effects and economic benefits of these data,with the prediction of water-bearing bed reaching an accuracy of over 95 percent.