An improved 3D modeling algorithm based on quasi tri-prism volume elements for geological body is put forward,this algorithm can be applied to the 3D modeling of complicated geological body(such as the geological body including the cavity,ore body,pinching and fault),also be used in the 3D modeling of the peculiar phenomena of geology such as mine and tunnel etc.,so it can realize the unified modeling of the geological body.With the aid of three-dimensional graphic library OpenGL,the visualization and any section view of geological threedimension model can be achieved by using this improved algorithm,this offers powerful support for excavating the information of 3D geological model.