The purpose of this study is to explain the necessity of the curriculum design model which can clearly reveal the compositional characteristics of school curricula. Moreover, this study is to support the basic logics of the design models and to lay the groundwork for improvement of the models by exposing its pros and cons. In this context, this study suggests three models. One is the Key Model, which is based on the core and the surroundings those are the most universal domain in school curricula. Next, the Octagon Model, which consists of subjects and extra-curricular domains. At last, this research proposes the Triangle Model, which is made to show the characteristics of career-based learning. All three models have different usages but when they are combined properly, they would provide help in planning a better school curriculum. All three models do not have to be utilized at all times for curriculum design at all levels. Each has different merits, and if they are improved and integrated that allows them to cover each other’s weaknesses, the contribution to future curriculum design fields in South Korea will not be small.