Three-dimensional GIS is more and more extensively used in the modeling and analyzing of geological bodies. It has the advantages of intuition, real and powerful analysis functions. The High-Cutting Slope is a special kind of geological body, which has its own characteristics and is necessary to be modeled in an integrated way. It is appropriate and efficient to develop a visualized and aided analysis system of the high-cutting slopes using the 3D GIS. By studying the 3D visualized modeling algorithms, we noticed that there isn’t an algorithm which can effectively model underground objects, ground objects and ground surface from the same viewport and at the same time, but it is needed in the modeling of the high-cutting slopes because of their characteristics and potential hazards. As a result of this, we proposed a new concept of underground ground surface-ground objects integrated visualization which points out the way to solve the problem of integrated model. Based on this new concept, we extended the data structure and modeling algorithm of 3D GIS, and implemented some relative functions such as: three-dimensional navigation, format converting from common GIS data formats, visualization of the integrated models and so on by using OpenGL and C#. We also implemented some spatial analysis functions such as spatial query and spatial plane slice based on the new data structure, and developed an information system which is currently used in the monitoring and early-warning information system for the high-cutting slopes in the Three Gorges Area.