Statistics show that, during the 12th Five-Year Plan period,1747 wells were drilled for drought-resistant water prospecting in Guangxi. The electric method had a 75% success rate in finding water in karst area and 10% in clastic rock area, showing remarkable difference. The difference in lithology and hydrogeological conditions between the clastic rock and the karst rock is the main internal cause of the great difference in the effects of the electric method. The stratigraphic lithology of the clastic rock area is mainly mud rock and conglomerate rock, among which, the siltstone and fine sandstone in the mud rock and sand rock have poor water content conditions. This kind of rock is a low-reisitivity rock ,which is an interference layer of electric water exploration rather than a target stratum. Coarse sandstone and conglomerate in sand rocks belong to hard and brittle rocks, which are likely to form fissures and water. This kind of rock belongs to high resistivity stratum,which is the main target bed for electric water exploration. In the clastic rock area, the upper part of the layer with significant changes in the lithofacies is developed by fracture propagation and is rich in groundwater. Based on the case analysis, this paper summarizes the experience of electrical water prospecting in clastic rock mountains, and provides a reference for the future electrical water prospecting in clastic rock areas.