The ecological survival of resource-extractive cities like Hegang hinges on how effectively their green infrastructure connects across fragmented urban and regional landscapes. Moving beyond traditional single-scale assessments, this research integrates established GIS and network analysis protocols to diagnose the multiscale connectivity of Hegang’s ecological network. By identifying 40 regional and 10 urban-scale sources, we built a comprehensive resistance framework that accounts for both mining-induced disturbances and urban expansion. Our findings reveal a precarious structural dependency: the entire cross-scale system relies heavily on a single “backbone” path, creating a bottleneck for ecological flows. Specifically, Node 2 in the western sector emerged as a vital node with high degree centrality, functioning as a primary gateway for regional biodiversity into the city center. Rather than seeking purely theoretical novelty, this study translates these topological insights into a three-tiered planning strategy – strengthening cores, adding paths, and cultivating nodes – offering a concrete spatial blueprint for planners to prioritize restoration efforts in declining industrial regions