Abstract: As China shifts from an era of incremental growth to one of stock-based development, urban renewal and the enhancement of spatial quality have become paramount. Urban design serves as a critical technical instrument in achieving these goals. However, evolving societal needs, shifting design philosophies, challenges from modern technologies, and reforms in the spatial planning system have rendered traditional urban design theories, methods, and paradigms increasingly inadequate, leading to theoretical and practical disputes. Addressing these new challenges, this paper systematically elaborates on the new people-oriented design concept, the green and intelligent design methodology, and the emerging paradigm of spatial development design. It explores new concepts, such as shifting from mere physical form design to comprehensive spatial development design, implementing multi-dimensional spatial design across all domains and elements, and facilitating multi-level collaborative design throughout the entire process. Spatial development design is defined here as value-driven design that encompasses the entire lifecycle—planning, construction, management, and governance—while adapting to future societal and technological trends. By establishing this new conceptual and methodological framework, this paper offers fresh insights for advancing modern urban design to align with the requirements of a new era.