During the last decade, knowledge about the impact of construction on ecological and human health has expanded significantly. Alternative techniques and products, designed to reduce these impacts, have developed in an aren known as sustainable construction, or green building. Taipei Public Library concerned with sustainable culture in terms of the environment al impact of the building and its long-term operation. In keeping with this concern, new branch library's design should consider building systems that demonstrate innovations in sustainable design, using architecture, electrical, structural and mechanical engineering concepts, which are mutually integrated and synergistic.This article mainly introduces the definition of green buildings, demand of green building, the experience of the Taipei Public Library in planning Pei-Tou and Shih-Pai Branch Libraries and the features of four green libraries in the world.