This research aims at proving the fact that the forms, spaces and many other design concepts of Modernism are much related with the changes of materials, struc-tures, and the way of construction as well as the idealis-tic and aesthestic things through the history of steel, one of the most important materials of the style. The meaning steel has in the modern architecture can be studied in the structure and industrial production system. 1) Steel frame broadened the range of understanding the space and created the new form through the skeleton/skin structure by reinterpreting the existing space fac-tors while it was being adopted to the architecture. Walls could be freed from the traditional function of bear-ing wall and roofs gave the transparancy to the interior by being linked with the glass. Posts lost the function which confines the space in the frame of the grid system and gave the flexibility to the interior due to the economical materials. These changes made the movable partition, screen with various materials and the system furniture which divides the space more important. 2) In the aspect of the industrialized architecture, it be-came the moment that the most of the archtectural com-posing parts were in mass production as they were standarized, high qualified, and generalized by the indus-trial characteristics of steel, and the specialization of structure and cladding, but the neither of the efforts to make the building itself by mass production or to standarize it was fulfilled. The high-tech architecture which borrows its archtectural manifestation from the high technology, however, is consistently paying efforts on such industrialization.