Prefabricated building, as a representative of modern architecture, has been vigorously promoted, and the traditional problems of large on-site labor and long construction period have been well solved. At present, the development focus of prefabricated building has shifted to the stage of low-carbon, environmental protection, green and energy-saving sustainable development. Whether green and low-carbon design is considered in the planning and design stage has the greatest impact on the whole life cycle of the building. Therefore, this paper mainly summarizes the concept and importance of green and low-carbon building design; The paper points out the embodiment of green and low-carbon concept in prefabricated building design; And how to calculate the carbon emission in the design stage; In view of the prefabricated building design stage to achieve a better green low-carbon state of optimization countermeasures.