The 25 acres site is located in the heart of Bangkok. Inspired by wind and pedestrian movement of Siam Square, which is an open air space that also functions as a transitional space; people are using Siam Square as a shortcut to various destinations because of its central location. Currently, Siam Square structures are mostly four-storey buildings but the usage is appeared only at the ground floor. To redesign this, the main concept is to create a dynamic flow of Siam Square by integrating green infrastructure into the unactivated areas (2nd, 3rd and 4th floor) resulting in an increase of land value and rental area. The design also revives old circulation and linkage and proposing for better ones. The research and analysis are focused on wind, pedestrian and energy of Siam Square. This project contains the divergence of design typologies which are suitable for particular areas.