Abstract: Three-dimensional digitization technology has been widely used in the design and construction stages of power transmission and transformation engineering, but it is relatively seldom used in the pre-project planning and decision-making stage. The construction scale of substation engineering is large and the site selection conditions are complex. Therefore, the overall site planning scheme in the early stage of the project is particularly important for the project construction. It is difficult for the conventional two-dimensional drawings or text to express the design intention visually. Through the analysis and research of multi-source heterogeneous BIM and GIS data, the problems of inconsistent software platform, poor data compatibility, and difficult integration of GIS and BIM data are solved. The three-dimensional visual display of the overall planning scheme of the substation site under real scenarios is realized,which aids the preliminary decision-making of the project and improves the efficiency of communication and decisionmaking. It is helpful to promote the three-dimensional digitization construction of the whole life cycle of the power transformation project.