For the shortcomings of the BIM+GIS integrated architecture platform, this paper proposes a technical architecture solution of the BIM+GIS integrated platform based on the WebGL 3D engine. This paper transfers the corresponding data through the web service interface by using the WebGL 3D engine as the main integration container. Then it hierarchically integrates the BIM IFC model data with the GIS as the framework, and finally forms the overall technical architecture of the BIM+GIS platform for urban rail transit engineering. After being applied in rail transit engineering, the technical architecture has been proved to be feasible with an advanced technology, which is of extensive promotion values in the field of urban rail transit engineering.