Transforming the global legacy of abandoned industrial landscapes into vibrant, sustainable urban assets presents a critical yet complex opportunity, requiring solutions that simultaneously honor heritage and meet evolving urban demands. As multifunctional public spaces, their vitality significantly affects spatial quality and user engagement. We investigate the spatial vitality of post-industrial landscapes through a multi-source data framework, using Beijing’s Shougang Park as a case study. Integrating spatial syntax, point-of-interest (POI) analysis, and Baidu Heat Map data, the research constructs a comprehensive evaluation model encompassing spatial accessibility, functional diversity, heritage openness, and crowd dynamics. The findings reveal a marked spatial imbalance in accessibility, with global integration values ranging from 0.09 to 0.29 and a low intelligibility coefficient of 0.09, underscoring a mismatch between spatial structures and modern functional demands. The study identifies dynamic openness of heritage spaces and integrated community functions as key drivers for revitalization. Optimization simulations demonstrate that restructuring road networks significantly enhances spatial integration, increasing the global integration range to 0.10–0.87. This research contributes a replicable, data-driven framework for assessing and guiding the renewal of legacy industrial sites, offering valuable insights for post-industrial urban regeneration and heritage-based development.