Abstract: Based on NURBS techniques, a new modeling approach for reconstructing complex 3D geologic body realistically is presented. First the digital terrain model is simplified to meet the demands of geologic body reconstruction. Then a variety of geologic structural planes are constructed conforming to the original geologic information and interpreted data. NURBS surface is constructed to fit all these predefined conditions. Based on this global model, a series of visualization analysis for 3D geologic information could be realized. An example of its application in hydropower engineering project is illustrated. It shows the feasibility and validity of the proposed approach for satisfying actual demands.