EIA has been introduced as a tool for environment protection into promulgation of the Environment Preservation Act in 1977, which replaced the Pollution Control Act in Korea. EIA system has been improved with the enlargement of project type, public participation, guideline improvement, and regulatory development. Recently, Environmental Impact Assessment(EIA) Act will have an important role for sustainable development. This article deals with regulatory development, implementation order, EIA project type, and EIS preparation guidelines by Act promulgated and amended, also it explains comparison analysis of Environmental Policy Act and Environment Impact Assessment Act Major results are summarized in the table.