Research on Coupling Coordination Level Between New-Quality Productivity and Industrial Structure Upgrading in the Yangtze River Economic Belt Urban Area

New-quality productivity and industrial structure upgrading has become a primary area of concern with respect to regional economic transformation and sustainable development. Based on static panel data of 108 prefecture-level-and-above cities in the Yangtze River Economic Belt from 2013 to 2022, the projection pursuit model, coupling coordination degree model, and obstacle degree model were used to study the spatiotemporal patterns and key obstacle factors in the coupling of new-quality productivity and levels of industrial upgrading. Results show the following: (1) The average coupling coordination degree increased from 0.42 in 2013 to 0.53 in 2022, exhibiting a three-stage trend of “initial advancement, rapid growth, and high-level fluctuation”. (2) Regionally, a gradient pattern of “downstream leading, midstream following, and upstream catching up” persists, but regional gaps have narrowed significantly. (3) Spatially, the coupling coordination level shows a pattern of “high in the east, low in the west, led by the core, and breakthrough in the local area”, with significant positive aggregation characteristics. (4) The main obstacle factors across the entire area include digital patents (7.03%), green patents (7.03%), and the number of high-tech enterprises (6.96%), but the weights of the obstacle factors vary greatly across different areas. These findings provide scientific support for green transformation, regional integration, and sustainability-oriented industrial policy design in the Yangtze River Economic Belt.