The goals of this study were to development Natural Ecosystem Value Assessment Model, to suggest the practical applicability of the Natural Ecosystem value assessment for development areas, and to assess natural ecosystem quantitatively using GIS. The Model can evaluate Natural Ecosystem Value between before and after land developments. To select indicators for the model, we conducted the literature reviews. and six indicators and the standard of evaluation had been developed through the expert interviews and literature reviews. the relative importance of the evaluation index throught two times expert questionnaires was found out. the Natural Ecosystem Value Assessment Model has been established, The results demonstrate that although the suggested six indicators are arranged by priority, to maintain quantitative and qualitative the natural ecosystem value, all indicators are desirable to be maintained complementarily. The findings of this study suggest that the natural ecosystem value assessment model appears to be effective an assessment for damaged natural environment value and possible to assign a score value. Also, this model can be applied to research areas and has implications to help maintain the natural ecosystem in land development districts.