The purposes of this study are to review characteristics and research areas of environmental studies; to compare and analyze environmental studies in research classifications and Korean societies from Korea Research Foundation(KRF) as well as decimal classification systems such as KDC, DDC, NDC and to suggest several modifications for environmental studies in KDC for the next edition. First of all, environmental philosophy, environmental sociology, environmental education, environmental toxicology, environmental architecture, and environmental geography are suggested to add to the main schedule in KDC and -0276 green technology(environmental technology) is suggested to add to Table 1. Standard subdivision. And new classification numbers for environmental law and environmental public administration are suggested in law and public administration.