The integration technology of building information modeling (BIM) and geographic information system (GIS) has become the management foundation of power grid engineering in planning, design, construction and operation and maintenance stages. However, the electrical equipment is not integrated on BIM and GIS, and the transfer technology of electrical equipment model data between BIM and GIS platforms is lacking. For this reason, the method of graph mapping is used to build the mapping rules between IFC and CityGML (common BIM and GIS data formats) to ensure the accurate mapping between the two organizational structures. The transformation of geometric information and semantics is emphatically analyzed. Considering the differences in organizational structure and information richness between electrical equipment and buildings, the organization form of IFC documents for electrical equipment is analyzed and a conversion framework suitable for electrical equipment is developed. The transformation framework proposed in this paper is extensible and can be used as the basis for building other spatial object mapping patterns in BIM and GIS.