The design competitions introduced for the first time in 1980s have played significant roles in developing the fresh ideas and concepts in housing design. As a result, multi-family housing was a little removed from uniform and monotonous. According to generalization of design competitions since 1990s, various design methods was keep trying in high-rise apartment housing. Therefore, the type of unit plan and design characteristics would be appeared comparable change. In this context, this study analyzed the design characteristics of unit plan and their trends applied in high-rise apartment housing. Because the Sejong city project housing design competitions were the most recent and foremost architectural firms and construction companies in Korea were participated in the Sejong city project.