Abstract:This paper sorts out and maps the components of dougong wooden structures along the west river of the Forbidden City, analyzes and discusses the shape and relationship of each component of dougong wooden structures through statistical comparison of component data, and finds that the structure of the components of dougong wooden structures is the same, the practice is consistent, and the shape is unified, in which the components of pingshen can be assembled, while the components of Jiaoke and zhutouke can be assembled into three layers. Through the investigation of historical archives and oral history, it is speculated that the investigated dougong wooden structures is Beishangmen dougong wooden structures component, and it is verified and speculated from the shape and practice of Beishangmen and historical surveying and mapping data.