Abstract
Mies van der Rohe is still known as the architect whose influence is the largest among modem architects. As his work is typical of modern architecture, the architecture of Mies shows an interest in materials and techniques, even though It established the new architectural world by glass and iron, and only transparency is emphasized with glass. So it is blame for the loss of peculiarity a result of thinking In the way of sachlich with expression and structure of material and hierarchical relation. Vincent Scully has insist on that an appearance of modem architecture be occur not by simply a technical request of a technician but by reflection of the times and times' spirit. In this means, the works of Mies is the trial to express the new times' spirit that the new times order and an understanding of material properties about glass with new material of modern. For that, this study tries to consider that Mies'work is the new trial through reflection of material to express about the bstraction beyond the limit of sachlich expression, on the point of expresslonal characteristics of material shown in plan of the Barcelona Pavilion and skyscraper and on the basis of the theory of Gottfried Semper and Karl Boetticher that architectural surface Is a medium which can define space and also express mass.