Industrial transformation and upgrading is a key variable for developing countries to become developed countries. In China’s institutional environment, the central government’s decisions regarding the spatial allocation of land resources cause a differentiation in the evolution of industrial structures and formats among regions, generating significant impacts on urban industrial transformation and upgrading (UITU), with important policy implications. Using panel data from 276 prefecture-level cities in China from 2007 to 2019, this study constructs a spatial panel econometric model and a mediating effect model to reveal how land spatial misallocation (LSM) affects UITU. The results show that, LSM is not conducive to UITU, and this adverse effect is greater in cities with a relative land supply shortage than in cities with a relative land supply surplus. Further research finds that the LSM caused by the relative land supply shortage affects the UITU mainly through intermediate mechanisms that crowd out the investments and financing for real industries and inhibit residents’ demand and innovation, and the LSM caused by the relative land supply surplus affects the UITU mainly through intermediate mechanisms that enhance the survival of low-end industries and disrupt the institutional environment. From these findings, this study not only puts forward specific policy recommendations for optimizing the allocation of land resources in China to promote UITU, but also discusses the implications for related research and practice in other countries.

Under the background of green development, the spatial structure of urban agglomerations (UA) has an important impact on urban land use efficiency (ULUE), but few studies have explored the impact mechanism between the two. This research explores the impacts of polycentric development on ULUE of UA, using data for 140 cities in China’s top ten key UA covering the period from 2004–2019. The linkage between polycentric development and ULUE is explored by estimating models of determinants of ULUE. This research also examines the mechanism of the polycentric spatial structure of UA on ULUE by using a moderated mediation model. The main findings of the research can be concluded as below. The eastern UAs show a mostly polycentric spatial structure, whereas the central and western UAs show a weak polycentric spatial structure. The polycentric spatial structure of UA has a positive impact on ULUE. An inverted U-shape curve depicts the relationship between the polycentric spatial structure of UA and ULUE. However, the mediating variables, integration of industrial structure and factor mobility have a positive and partially mediating effect between the polycentric spatial structure of UA and ULUE. The infrastructure level has a positive U-shaped regulation effect, in which the impact coefficient of transport infrastructure is more significant. These findings provide empirical evidence for the coordinated development of China’s regional space planning and ULUE.