Against the backdrop of China’s shift from urban expansion to stock regeneration, waterfront post-industrial heritage parks face the dual challenge of cultural heritage conservation and ecological restoration. Unlike conventional renewal projects, these sites suffer from impervious surfaces, pollution, and fragmentation, yet current design practices prioritize industrial aesthetics over stormwater management and water resilience. Given increasing extreme weather and non-point source pollution, transforming stormwater from hidden engineering into a visible driver of ecological and cultural activation is a critical design challenge. This study adopts stormwater management as its analytical lens, integrating Water Sensitive Urban Design (WSUD) and Sponge City concepts to synthesize infrastructure with public realm design in industrial heritage sites.