This research examines the intertwined challenges of urban shrinkage and demographic aging in China's Yangtze River Delta (YRD) region, where nearly half of cities exhibit local shrinkage while elderly populations exceed national averages. Through regional analysis and interviews with officials in four cities, the study reveals systematic contradictions between demographic realities and policy implementation. Despite negative population growth, growth-oriented development models driven by GDP-centric evaluations pose hidden risks for future urban decline. Based on perspectives framing aging as an opportunity for societal restructuring, this research analyzes East Asian top-down planning strategies (Japan's networked compact cities, Singapore's age-friendly planning, and South Korea's smart aging initiatives) and identifies structural governance barriers in the YRD cities. The paper aims to provide insights for addressing these dual challenges, ultimately contributing to adaptive planning approaches for sustainable urban futures.