Abstract: Based on the extensive development of underground space and project,the concept of geo-digital underground space and project(Geo-digital) was presented by use of technology of GIS,graphics,database,numerical analysis and network communication.The target was to establish a high integrative,exoteric and incorporative geo-digital information system which included the geography,stratum investigation,design,construction,monitoring,project detection and operational maintenance.The method and technology to create geo-digital database model were mainly discussed and an example was demonstrated for its application.Geo-digital database model would support spatial inquiry,constructing process simulation,project lifecycle management,real time monitoring and data mining,etc.Furthermore,it would not only play an active role in the sustainable development of underground space,but also bring great economic benefits.