Positive or Negative? Industrial Economic Performance of Polycentric Spatial Structure in Harbin

In recent years, polycentric spatial development has been widely regarded as an effective strategy for cities to address various urban challenges. However, conclusive evidence remains limited regarding how and under what conditions polycentricity enhances agglomeration efficiency. The study selected Harbin, a multi-center city in China with a population of over 5 million, as the research subject. Using the breaking point zoning method and the double-standard employment density method, we identify the polycentric spatial structure at the community scale. The industrial economic performance of this polycentric structure is evaluated through three indicators: contribution performance, relative performance, and development performance. The operational state of industries is further analyzed using the quadrant method. Moreover, we microscopically examine the relationship between polycentric structure and economic performance across different industries. The findings reveal that in urban centers, certain industries simultaneously benefit from agglomeration effects and reduced investment costs, aligning with traditional perceptions of polycentric structures. However, other industries exhibit negative economic performance. Agglomeration economies and diseconomies coexist not only across different industries but also within the same industrial categories. Key influencing factors include the threshold of industrial agglomeration economy, spatial environmental factors, enterprise scale, and average investment intensity. Building on these results, the study provides policy reflections on industrial agglomeration strategies in polycentric cities.