The purpose of this study was to search the possibility to utilize materials in creative designs through examining the relationship between design materials and form by analyzing form by materials in the process of designing. In order to achieve this purpose, the objects to analyze designs were limited to chairs and lighting fixtures, and the period of analysis was also limited on 20th century. In this study, it was understood that changes of design materials and forms characterized by years. The period, when materials were used, was similar by design items, but the forms were different though they were same materials, and the same combinations of materials also changed whole forms. Also, it was found that design materials were affecting the change of forms if it is considered that whenever design materials were characteristically changed, forms were also peculiarly changed. Therefore, the result of this study might be utilized more effectively by design items and by structural elements even in each items, are arranged, connecting them with the trend of design.