Ever since the industrial revolution, large cities have become a field of new lifestyle and urbanization, causing climate change and environmental pollution. As a result, countermeasures for revolving these problems is needed. In addition, large cities in the information age have become a space where each nation executes its public policy to express the competitiveness of each city. In this study, countermeasures for the environmental crises caused by urbanization as well as the sustainable spatial designs for the cities are investigated as a new source of urban competitiveness, and the environmental aesthetics for designing public space is considered. The purpose of this study is to suggest a direction for sustainable designs and planning that is applicable to public space. According to the definition of sustainability, the items of the spatial implementation of ecological, economical and social sustainability are categorized. Based on this categorization, the sustainable designs of public space are classified into five types, and a comprehensive analysis of good public spaces from previous literature is conducted. The concepts of design and three elements--public space, sustainability, and their instrumental meanings, are integrated in this study. The significance of this study lies in the actual application of the classification to the planning and design of sustainable public space in cities, rather than being a conceptual classification.