As library have become changed. Beyond conventional simple functions such as data storing and recording, the functions of modern public libraries are expended to various directions, for example functions of encouraging residents to utilize information and participate in cultural activities and also a function of life-long education, resulting in playing a role as complex space. As the role of public libraries changes into a complex one, spatial planning reflecting this change is required. Spatial arrangements, furniture arrangements and interior images in 12 public libraries in Seoul were analyzed. As a result of the study, it was found that in spatial arrangements, many public libraries linked spaces by functions. Furniture arrangements have been changing from the closed arrangement to the open arrangement. Interior images were identified as static and simple except digital information space. Accordingly, public libraries have became needed to play a proper role of community facilities for local residents by planning furniture arrangements and conducting interior designs taking characteristics of many different users into consideration.