A rapid conversion to urban land use, including urban sprawl, resulted in a variety of environmental problems, one of which, for example, is the increase of NO2 emission. Since the early 1960s, immigration to the capital Seoul and to its extended areas of Incheon City and Kyunggi Province has continued as a consequence of rapid industrialization and urbanization. Presently, almost 48% of the Korean people reside in these areas, officially termed as ‘Seoul Metropolitan Area’ (hereinafter referred to as SMR), which only composes 11% of the total territorial area. Therefore, the Korean government is trying to formulate several policy projects including the New Multi-functional Administrative City issued. In order to predict the spatial change and to suggest the eco-efficient strategies of the future urban land use in the SMR, this study develops an urban dynamics model for urban growth, population and NO2 emissions. The eco-efficient land use is defined as "the minimum developed area compatible with population size and environmental pollutants discharged, the maximum of biological resources including green density and adsorption of environmental pollutants" on the basis of the various literature survey. From the quantitative analysis of the land use change and related policies review, this research draws attention to a number of issues including the supply-oriented urban land use policy, lack of the land banking and its re-utilization, and absence of the integrated planning process between urban land use and environmental management, etc. The future urban land use policy needs to save land resource and to strengthen the interconnection between land use and environmental management. The urban dynamics model consists of two types of modeling: One is an augmented model that covers the SMR as a whole, and the other is a regional model that is divided the SMR into 16 parts. The augmented model suggests that 25.3-25.7 millions of people and 2,422 ㎢ of developed area can be included in SMR through three scenario analysis. The regional model shows that 22.7 millions of people can be comprised based on the most conservative scenario, and Incheon city is also required to be developed and managed as the Air Pollution Sensitive Area. The total populated area requires to be controlled carefully with due regard to the decrease in population after 2030 year. As well, the behavior of future urban land use in SMR is simulated according to the development potential of every grid (500m×500m) based on the GIS-based planning support system. Then it is reviewed as the impact of the ecological network of SMR. To construct a more reasonable and comprehensive urban dynamics model for urban land use management, it is needed to extend to cover the CO2, PM10 in air quality modeling and water quality modeling as one body, or at least to divide business sector into industry and commercial land use in the further model. This research, thus, has a great potential as the first step to connect an urban dynamics model and a GIS model of Korea.