The Environmental Impact Assessment(EIA) System has grown up as an adult today in Korea(ROK). It seems that we have only focused on the specific and technical aspects of the assessment without looking at the whole concept during the past 20 years. Thus we have accomplished quantitative growth but not qualitative development at all. This is the right time we should reconstruct the concept and move into the step for qualitative development. It is expected that the corpulence of the EIA system would be enlarged due to the introduction of integrated impact assessment system. It is necessary to introduce a newly designed method into the EIA methodology and improve the Environmental Impact Assessment based on in order to accomplish and manage more effective EIA system. To the conclusion, it is highly necessary to formulate a wholly new system which can be useful to improve the existing various systems and to follow the fundamental concept of EIA.