This study based on GIS thinking explores the combination of the mixed spatial data model and GIS model to build three-dimensional(3d) model of geological bodies in the ArcEngine platform, describes the interface and method used in the construction of 3d geological body in ArcEngine component platform in detail, and puts forward an indirect method which constructs a set of geological grid layers through Kriging interpolation by the borehole data and then converts it into the geological layers of TIN, which improves the defect in building the geological layers of TIN directly and makes it better to complete the simulation of the real geological layer. This study makes a useful attempt to build 3d model of the geological body based on the GIS platform, and provides a certain reference value for simulating geological bodies in 3d and constructing the digital system of underground space.