The purpose of this paper is to examine the common characteristics of late 20th century interior design style and the post-modern thinking system. A period has its own predominant spirit which determine the tendency of art, and the ubiquitous power in the spirit decides the period's pattern of art. Therefore the interior design style belongs to general art sphere that has its own individual character derived from the dominant power of the controlling system. Paying special attention to this understanding, the auther has processed this paper by combining the post-modem thinking with special characteristics of each of the 20th century interior design style. Until now, researches have been focused on the individual style of post-modern design; however, a general research comprising the whole characteristics of expression has not been made. Accordingly, the rationale of emphasizing the general point of view is establshed. Also, this study suggests a model applicable to studies concerning other art area. This type of methodology is receving more attention as an approach investigating new art ideology for researching post-modern thinking and late 20th century art styles. The conclusions are as follows: First, the distinctive expressions of postmodernism appear to be characteristic of illusion, metaphor, pluralism, decoration, and symmetry, Those of late modernism appear to be the characteristic of complicated simplicity and symplified complexity, passiveness of symbolism and harmony, indeterminacy of form and space, and unintentional decorativeness. And the characteristics of deconstructionism are spatial difference and temporal defferal, and un-reductive and non formal abstractiveness of the space, unfinishness, chance, and secretiveness of individual style. Second, the disinctive expression seems to share common characteristics with postmodern thinking. The best examples are pluralism, non-formalism, populism, and historicism, originating from the deconstruction of 'meta-narrative'. Third, based on the second conclusion, general distinctive expression could be simplified as chacteristics of plurality, hybridity, and indeterminacy. These expressive chacteristics appear to be automatically connected with general postmodern thinking. Last, in consideration of the above conclusion, the extreme generality could be distinctively clarified as 'textural co-exsistence'. Accordingly, the author might confirm that 'textural co-existence' originated from the text that comes from postmodern thinking. In conclusion, design expression of late 20th century interior design accepts the ?universal theme of ubiquitous postmodern thinking. And universal expressions and supreme generality can be common analysis tools for understanding and studying complicated late 20th century interior design.