Abstract: hydropower station dam Foundation rock of karst caves, karst fracture zone and tectonic development of broken rock such as defect control, prone to subsidence, leakage, resulting in power plant engineering deformation and instability. Karst development and structural change of carbonate rock is very closely connected, therefore, accurate diagnosis of the hydroelectric power station dam Foundation rock mass defect was significant. This use of perspective and CT Imaging of electromagnetic wave between holes, underground concealed carbonate rock structures in non-uniformity, corrosion crack belt interface, fractured structure, nature of crack filler and geometric spatial form for digital descriptions and characterizations. Combined with a hydropower station dam Foundation in Guangxi natural properties of carbonate rock structures, changing characteristics of rock mass structure of the measured data, further analysis in engineering under the action of stress distribution, deformation law of rock, forecast and found seepage of dam Foundation and stability and thus reasonable to develop effective treatment measures.