This study is to find mental element and principle for building as the side of tranditional ideas and to understand dwelling from and style by this wag. So we can understand yang taeg theory as a part of feng shui that controls the mental, field of traditional architecture. The results may besummarised as follows. 1. Mentalprinciple of traditional architecfure being understood as a "역" is to result is not the concept of shape as materials and in but that of phase as a spririt. 2. In yang taeg theory, architectural behavior (as selecting site, building and the day for building) is made form the base of that, a human being as a part of universe. 3. Geomantic aspect, to being, laid in an fying a human being and nature as spatial, time concept. 4. The concept of domain in feng-shui is found in village as well as in house.