Recently in connection with the development of network technology, GIS researches shift their focuses to openGIS which enables to share heterogeneous geodata and geoprocessing resource under the environment of LAN and WAN. This study proposes an easy method to develope GUIs which enables openGIS in the intranet environment. In the developing stage of GUI, the most important thing is to develop effective windows programming technique and apply a internet linking technique to developed GUIs. This study shows an internet linking technique and a GUI developing method using OLE automation and ActiveX/COM standards. Using a case study of Taegu City Library, the study constructs a GIS database and develops its GUI which performs map overlaying, referencing attribute tables, drawing up of thematic map, buffer analysis, and statistical calculations. This study remains same further research areas of developing a new advanced technique for openGIS and its GUI using distributed object model of CORBA, Java language, and JDBC data accessing technique.