This research was carried out to show the method of preserving high-grade farmland or Agricultural Development Area to contribute to the self-sufficiency of food as well as promotion of industrialization and urbanization, which has reduced 22,000 ha of farmland per year during last 10 years. However, in securing housing estate areas, the farmland conservation policy conflicts with housing supply policy for demands on more comfortable dwelling life for people, which leads to serious situation in Capital Circle of living more than 50 % of total national population. Therefore, this presents the method of fulfillment both the farmland conservation policy for self-sufficiency of food and the housing supply policy for proposition of securable residential areas.