Firstly, through orthogonal experiment, this paper optimizes the fusion scheme for seamless connection of the Revit model for the foundation pit supporting structure and the Civil real three-dimensional geological model; thus, solving the difficulty for Revit to directly create the real three-dimensional geological model at present. On the basis of this scheme, a series of fine modeling methods for common supporting structures of foundation pits such as pile, anchor, surface and layer are explored and summarized. Finally, in the context of actual project cases, the preliminary application research of the comprehensive model for supporting structures of foundation pits under the BIM concept is carried out in the field of computer aided design: three-dimensional concretization and roaming display, collision check of supporting structures and the surrounding underground precast piles, accurate calculation of work quantity, design optimization of space intersection joints of different supporting structures, sectional observation of the three-dimensional spatial attitudes of the groundwater table, the poor weathered bedrock surface and the silt layer, the two-dimensional CAD supporting pile position plan which can be used to guide accurate measurement and setting-out, etc.