Abstract: Filling algorithms based on unorganized discrete points were proposed to build geological entities by analyzing the 3D scene models on the ground and 3D orebody models underground. Combined with the methods of developing geographic information system(GIS)， a ground and underground 3D visualization information system was constructed according to an iron mine in Liaoning， which includes the functions of fast modeling， 3D browser and display， spatial attribute query， interoperate measurement and spatial analysis and so on. With the system， 3D models of ground and underground entities enable to be built， queried， measured and edited， and the problems that can be only displayed were solved. Besides， the terrain characteristics and the spatial distribution of mine geographic information were observed at both macro and microlevel， and then the 3D geographic information entities in the mine were expressed more intuitively and comprehensively， which could be the foundation of digital mine and intelligent mining.

Key words: ground and underground 3D GIS, algorithm fusion, 3D model construction, model upgrade, system development