In the development of green buildings, the conceptual design phase determines the whole-life-cycle environmental performance and comprehensive benefits. However, traditional conceptual design methods face bottlenecks such as low efficiency and strong dependence. As a new type of digital tool, generative artificial intelligence (Generative AI) can promote the optimization of green building conceptual design and effectively improve building effects through its capabilities in data learning and goal-seeking. Starting from the conceptual design phase of green buildings, this paper analyzes the application value of generative artificial intelligence and proposes specific application and practice strategies, aiming to promote the in-depth development of green buildings and provide reference for the subsequent optimization of the green building conceptual design phase.