Abstract: The idea of an integrated representation of outdoor and indoor in CyberCity GIS is put forward in this paper.Firstly,the difference between the representation of 3D buildings based on CAD and that based on GIS is introduced.The applications of 3D buildings based on GIS can not only implement some basic 3D GIS functions but also be combined with DEM,DOM and DLG data.Secondly,data management methods for outdoor and indoor scenes are discussed respectively.A pyramid structure for DEM/DOM data management and an R⁺ tree index for 3D vector data management in outdoor scenes are introduced.A subdivision method for floor plans in indoor scenes is discussed.Thirdly,dynamical visualization methods for outdoor and indoor scenes are discussed respectively.The LOD method and the memory paging technique are applied in outdoor scenes.The visibility method is applied in indoor scenes.Fourthly,the indoor is compared with the outdoor from some aspects such as dimensions,amount of data and visualization,fundamental data,objects,editing function,interactive querying function,and statistics function.Lastly,the idea of an integrated representation of outdoor and indoor in CyberCity GIS is summarized from vision,dynamical interactive walkthrough,data organization and management,GIS functions,and data loading.