The purpose of this paper is to present the environment change of Cheju Island as land development process using GSIS(Geo-Spatial Information System) technique. We implemented the process based on the maps of soil color, underground water pollution points, land use, land development planning and land sight seeing supported by Cheju Province Office. To use the maps for GSIS data, first we transformed the picture data of the office into raster structured picture data using scanner. Second, the coordinate system was added to raster data using 1/50000 geographic map. Third, we estimated land planning process using GSIS technique(overlay and reclass technique). The results showed that land development effected the natural environment(forest, green field, farm land). However, the chemical pollution and land sight seeing was not so much effected by the land development that was found.