In the traditional planning and designing process of water conservancy project, there is a serious gap between the project visualization (“Visualization”) and the project calculation (“Calculation”). Usually, “Calculation” can not be guided by “Visualization”, and “Visualization” can not quickly reflect the result of “Calculation”. In order to resolve the disjoint between “Visualization” and “Calculation”, this article discusses the method of realizing the integration of “Visualization” and “Calculation” in planning and designing water conservancy project by adopting the technologies of Virtual Reality (VR) and Geographic Information System (GIS). The VR technology can provide a realistic, interactive and dynamic three-dimensional scene of the water conservancy project area by computer technologies. By this three-dimensional scene the analysts will get the immersive feeling even if they are not at the scene. GIS can provide the strong function such as spatial data storage and analysis, three-dimensional terrain analysis, and so on, to address its advantage in “Calculation”. So in this article, the three-dimensional virtual environment is built to express the terrain, topography and landscape of the project area, and with this three-dimension environment, the hydroelectric reservoir storage capacity, the submerged area and the volume of excavation and filling can be calculated.
