This study analyzes the problems of environmental laws, development planning laws, Metropolitan Area Development Planning (MADP), and the level of environmental pollution at Asan-bay metropolitan area, where MADP will be realized in the near future. In order to prevent environmental pollution by the implementation of MADP, the Environmental Impact Assessment (EIA) Act and EIA systems in Korea should be revised so as to reflect the followings. First, the impact of national landuse planning changes on the environment should be considered at the beginning of the EIA procedures. Second, the overlapping and greater impact of many projects upon surrounding metropolitan areas should be simultaneously evaluated, though each project is the subject of EIA, and the environmental pollution protection and abatement alternatives must be made in accordance with the above impact of the projects. Thirdly, total effluent regulation of water pollution, air pollution and solid wastes should be enforced based on the self-purification of the metropolitan area environment.