Due to the extensive terrain region and complicated irregular topographic form, great difficulties have been encountered during the design and construction of large-scale water resources and hydropower engineering. With the development of modern hydropower engineering, 3D digital terrain models have obtained wide applications, such as dynamic fill and dig of terrain, site layout, cruising of general construction layout, and 3D geological modeling. These are involved in all research contents of terrain visualization, including representation and transformation of digital terrain, multiresolution model, terrain simplification and terrain reality. Based on the example of Jinping first-level hydropower engineering, the TIN model in the dam area and the multiresolution model in the region of general layout were realized using Delaunay algorithm and multiple level of details technique, respectively. Finally, according to the special requirements of 3D geological models, the NURBS technique was introduced to rebuild the simplified terrain model based on TIN model. This NURBS model not only occupied small storage and had low accuracy loss, but also could be easy to operate and analyze graphics visually. The realization and successful application of these models will promote the development of hydropower engineering toward digitalization, visualization and intelligentization.