This analysis traces the change of the green area in the zoning of Seoul city planning during the 1960-80s to understand its morphological characteristics, as well as its relations to Seoul master plan. In 1966, the green areas were dispersed in the surrounding outer mountains, while in 1972, the scattered green areas were connected to form a ring-shape under the influence of limited development district, which was conceived as a green belt. In 1978, the linear green areas along the branches of the Han River were introduced to connect the Han River and the ring-shaped green areas. In the 1980's, the land development districts were so designated in the far ends of the green areas along the rivers that the network of the green areas along the rivers and the ring-shaped green area of the mountains were disconnetcted again. The former actually works as the 'edge' dividing the community units within the built-up area, while the latter prevents the built-up area from sprawl.