Traditional BIM model comparison techniques generally rely on the globally unique identifier (GUID) of components for version iteration analysis. However, single - software applicability of this technology conflicts with the requirement for multi-source heterogeneous model assistance in engineering practice. To address this issue, this paper first studied the data format based on Industrial Foundation Classes (IFC4.0), aiming to convert BIM models from different platforms and software into a unified IFC data format. This conversion process ensures lossless transfer and comparative analysis of BIM models between different platforms and software. Secondly, according to the IFC semantic dictionary standard, this paper organizes and classifies the models according to the project space model tree, thereby reducing the complexity of spatial comparison analysis in the models. In addition, by comparing spatial position information, entity pairs are formed, and the spatial projection area and intersection area method are used to determine spatial geometric consistency. Finally, the accuracy of the method was verified through actual engineering project cases, demonstrating its ability to accurately identify spatial differences between BIM models