Regenerating Urban Commercial Space: A Case Study of Kunshan Shangsha Street under the Three-Dimensional Urban Design Paradigm

With the increasing intensity of urban spatial development, traditional commercial streets are facing multiple challenges, including functional decline, spatial fragmentation, and environmental degradation. This study takes Kunshan Shangsha Commercial Street as a representative case and, based on the concept of “three-dimensional urbanism,” systematically analyzes its problems in spatial structure, traffic organization, and landscape interface. Through field investigation and spatial diagnosis, the study identifies core bottlenecks in urgent need of intervention and proposes an integrated renewal strategy encompassing spatial integration, circulation restructuring, and landscape synthesis. At the spatial level, a vertically and horizontally integrated pedestrian system is introduced to achieve efficient multidimensional connectivity. In terms of circulation, the main and secondary movement axes and nodal systems are redesigned to establish a layered, composite flow network. For the landscape system, ground-level green corridors, vertical greening, and cultural landmark nodes are incorporated to enhance environmental quality and spatial legibility. The findings provide practical guidance for the transformation of traditional commercial districts in high-density urban contexts and offer a feasible pathway toward spatial hybridization and ecological urban development.