EIA has been developed as a tool for environmental protection into promulgation of the Environment Preservation Act in 1977, with the introduction of EIA concept in the Pollution Control Act amended in 1971. EIA system has been improved with the enlargement of project type, public participation, guiderline improvement, and amendment of Act and presidential decree. Also, this system has been developed to reduce adverse effects affecting environment and human beings for environmentally sound and sustainable development. This study is to analyze contents of Acts and regulations relative to Environmental Impact Assessment from 1971 to recently.