Abstract: The technique of ground penetrating radar (GPR) is a high-tech technique for examination, which has a lot of advantages such as high degree of accuracy, non-stop operation, non-destructive, economical, rapid survey, audio visual and so on. We can identify abnormalities in object interior with GPR by transmitting electromagnetic waves of high frequency to object interior and receiving the backward waves.When applying the technique of GPR to water-power engineering, the author detected the interface between the overburden layer and the fracture zone of the earth slide in some hydroelectric stations and some of the solution cavities in the reservoir area of some pumped-storage power stations.