The sustainable design starts from the coexistence with the nature. Besides the direct and specific sustainable design such as energy saving, low carbon emission and resources recycling, energy- efficient design becomes on demand in terms of design process, construction, and maintenance. As far as the sustainable design is concerned, appreciation on the characteristics of the land and the climatic environment should come first. Especially, in South Korea with distinctive four seasons and large temperature differences in the summer and winter, it is critical to utilize the passive design in spring and autumn to minimize energy consumption. To that end, the targeted amount should be set first, and then, the passive design be applied to minimize the excess load to create the pleasant indoor environment as much as possible. This, in turn, leads to the utilization of the active design and renewable energy. Green Tomorrow has implemented the environment-friendly approaches by the passive design in its initial schematic design. And Korea¡¯s traditional concept has been introduced in this project. This has resulted in the realization of the eco-friendly architecture for the first time in Korea and raised the public awareness level on the sustainable design by acquiring the globally- acknowledged LEED Platinum certification for the first time in Northeastern Asia.