Abstract
Enhancing environmental quality of District-Unit Plan in Seoul is very essential because it is an important issue that sustainable development in a balance between nature and built-environment. Environmentally friendly design in a city generally recovers various types of nature surfaces such as vegetation, semi-open paving and greenery on rooftop and also links a green tract of land between inner space and outer space of District-Unit Plan. In addition, good environmentally friendly urban design generally provides an appropriate urban public space and gives beautiful urban scene and function. As the reasons above mentioned, Biotope Area Factor(BAF) will be applied for District-Unit Plan in Seoul. It may increase the quantity of nature area and enhance the quality of urban public space in Seoul.