The ideal housing in the 21st century means that it can provide people with the balanced life between nature and human life, while is possible through the systematic harmony of nature, environment, and human. As our society increasingly pays attention to the importance of environment, environment friendly houses and ecological dwellings are being built. If we add our own cultural environment attribute and historical identity to the ecological housing, we can create the most unique Korean ecological architecture. This study examines ecological interior expression methods from the traditional housing architecture which started out of nature, in order to find out an ecological approach in the interior design of the dwelling space. Based upon this examination, it mainly focuses on how these methods can be applied to a modern housing architecture. From an ecological perspective, the traditional house interior has two distinct characteristics; nature friendly and human friendly, because it considered nature and human harmoniously. The interior of the traditional housing can be divided into three types; nature friendly, health friendly, and human friendly. Finally, this study investigates the ecological value of the three types and application of them to modern housing. It will help to find out the harmonious way of building a house harmonizing both nature and human. Especially, considering that the nature is being destructed and the health of human is deteriorating due to the destruction of the nature, this study will show a feasible alternative to build the most Korean style of environmental architecture.