As the environmental concerns in Korea have shifted gradually from the environmental pollutions to the quality of life (QOL) enhancement, it has become increasingly important to implement comprehensive assessment of environmental quality as possible. This is the major reason to develop Environmental Assessment Index. This study focuses on indices development of factors in Environmental Impact Statement Preparation Regulation. Environment in this regulation is composed of natural environment, life environment and socio-economic environment, and it is composed of 22 factors. EAI(Environmental Assessment Index)studied in this research is integrated by 16 factors. It will contribute to public participation in Environmental Impact Assessment process and environmental policy.