Clarifying the intrinsic nature and formation mechanisms of the territorial spatial development non-equilibrium, optimizing the allocation of territorial resources, promoting regional balanced development, and alleviating regional development disparities have become common endeavors of all countries seeking to enhance development quality. This study, based on the land use and socio-economic data of 31 provinces and cities in China from 2006 to 2020, utilized the kernel density estimation method and ArcGIS spatial analysis to explore the spatiotemporal evolution characteristics of China’s territorial spatial development non-equilibrium. The research findings are as follows: (1) From 2006 to 2020, both the land development intensity and land supply capacity showed an increasing trend, with increases of 21.4% and 8.03%, respectively. However, their spatiotemporal evolutions significantly differed. (2) The state of the territorial spatial development non-equilibrium in China significantly improved, with a rising trend in the territorial spatial equilibrium degree. Regional disparities in the territorial spatial equilibrium degree decreased. The number of provinces and cities in a state of underdevelopment decreased from 23 to 8, while the number in an equilibrium state increased from 7 to 21. The central and western regions showed more significant improvements in the territorial spatial equilibrium degree and a greater reduction in regional disparity when compared to the eastern and northeastern regions. (3) China exhibited distinct regional disparities in the territorial spatial equilibrium degree. The overdeveloped areas were Beijing and Shanghai. The underdeveloped regions were primarily concentrated in western areas, including Sichuan, Yunnan, and Xinjiang. The high-level equilibrium regions were predominantly located in the southeastern coastal provinces and the central plains region, while the low-level equilibrium regions included Inner Mongolia, Ningxia, Qinghai, and the three northeastern provinces. (4) From the perspective of the number of agglomeration types, the order is HH (high–high) > LH (low–high) > LL (low–low) > HL (high–low), and China’s TSED exhibits a spatial proximity peer effect. The innovation of this study consists of the following aspects: (1) The clarification of the fact that the essence of equilibrium does not require an exact 1:1 match, as with “two horses”; rather, it entails the maintenance of a slight surplus of land supply capacity over land development intensity. This approach allows the possibility of future sustainable development by leaving room for expansion. (2) The differentiation between high-intensity conjugation (in terms of both quantity and quality) and low-intensity conjugation (quantity only) from a conjugate perspective. This categorization aids in a more comprehensive and in-depth understanding of the territorial spatial development non-equilibrium and its spatiotemporal patterns. It provides crucial information for the formulation of sustainable national territorial development plans and the promotion of a regional development equilibrium.

The regulation of land use within territorial spaces has, to some extent, inhibited the free flow of land resources, giving rise to the dilemma of substantial losses and profits within and outside regulated areas. Investigating how to allocate “windfall profits” to compensate the regions that suffer windfall losses is of great importance for addressing regional development imbalances. This study, based on the perspective of restricted land development rights, employed an improved Cobb–Douglas (C-D) production function to analyze the differences in land input contributions between the agricultural and non-agricultural sectors. It quantified the extent of restricted land development rights, assessed their value using the opportunity cost method, and applied an economic adjustment coefficient to revise the regional fiscal transfer amounts. The results indicate the following: (1) The contribution of land factors to economic output is more significant in the non-agricultural sector than in the agricultural sector. (2) There are substantial differences in the quantities of restricted land development rights and their unit values across provinces and cities. Anhui Province has the largest restricted area, at approximately 71,945.52 hectares, while Guizhou Province has the smallest, at about 6452.62 hectares. Shanghai has the highest unit value, at around CNY 13.77 million per hectare, whereas Yunnan Province has the lowest, at approximately CNY 1.4748 million per hectare. (3) The total fiscal transfer amount for the provinces in the Yangtze River Economic Belt is about CNY 23.4 billion. Anhui Province receives the most compensation, at approximately CNY 8.5 billion, while Jiangsu Province has the highest expenditure, at about CNY 19.8 billion. Currently, the state should establish a comprehensive regional fiscal transfer compensation mechanism that takes into account the fiscal payment capacities of “windfall profit regions” and the incentive effects on “windfall loss regions” when determining fiscal transfer amounts. This approach aims to alleviate potential fiscal payment resistance in “windfall profit regions” and enhance proactive protection efforts in “windfall loss regions”, thereby achieving the coordinated development of economic growth, ecological improvement, and food security.

As the spatial carrier, the high-quality development of land complements the high-quality development of the economy and society. Imbalanced land use severely restricts regional high-quality development. This study uses panel data from 110 cities at or above the prefecture level in the Yangtze River Economic Belt (YREB) from 2013 to 2022. Based on a conjugate perspective, it comprehensively considers quantitative balance and efficiency coordination to calculate the spatial equilibrium degree of land use. Kernel density estimation and Moran’s I index are employed to reveal the spatiotemporal differentiation characteristics. This study divides land-use spatial equilibrium into different types and proposes differentiated development paths. The findings are as follows: ① In terms of temporal evolution, the spatial equilibrium degree of land use in the YREB exhibits a nonlinear progression, overall trending towards stable convergence. ② In terms of spatial evolution, provincial capital cities and municipalities directly under the central government drive the development of surrounding cities, forming three major urban clusters in the upper, middle, and lower reaches. ③ The spatial clustering characteristics of land-use equilibrium in the YREB are significant, but the degree of agglomeration is continuously weakening. ④ The optimization paths for different types of land-use spatial equilibrium show significant differences, requiring differentiated governance. These findings provide a scientific foundation for optimizing the national spatial pattern of land use, advancing regional balanced development and achieving high-quality development.