The present study was performed to improve the Environmental Impact Assessment system by comparing and analysing EIA systems for Residential Developments in the light of the business practice. For the improvement of EIA system, future strategies from each of three part ; the organ of approval(Construction&Transportation Dept.) for residential developments, the organ of consultation(Environment Dept.) for EIA and a developer(Korea Nation Housing Corp.), were analysed, and EIA systems and the processes of Residential developments were analysed. Results from the analysis of problems have provided a proposal for improvement of the Environmental Impact Assessment.