Songdo G-Tower was designed to make a model of symbolic and eco-friendly new office as a new government office building in Incheon Free Economic Zone which encompassed Songdo, Young-Jong, and Chung-Ra. Four atriums reaching up to 6 floors and sky garden of 25m depth reverse-slope influence characteristic of a building as drastic and creative element. Formativeness of a diagonal line shown on the elevation of a tower building is simple and dynamic figure. Also atrium, a core eco-friendly environmental element, enhances the insulation performance of the building and provides users with various work and resting spaces by floor plans that are different on all 33 floors. It was planned to harmonize with integration and Independence of various programs in zoning plan for layout. The independence of three programs such as IFEZ government office building, UN and culture were secured by a layout of segmented masses, integrating the main lobby in the concourse with these programs, and having function to make users easily recognize and approach to every program.