<p>Understanding the complex mechanisms underlying agricultural space urbanization is essential for sustainable land management. This study identified the spatiotemporal characteristics of the agricultural space urbanization from 2000 to 2020 in China’s Yangtze River Economic Belt (YREB) using a kilometer-grid-based approach. By employing the partial least squares structural equation modeling method, the intricate drivers of agricultural space urbanization were investigated. The results revealed that from 2000 to 2020, agricultural space urbanization in the YREB covered an area of 28,198 km², accounting for 84.5% of the total increase in urban space. The partial least squares structural equation modeling analysis revealed regional variations in agricultural space urbanization dynamics. In the western YREB, where urbanization is in its initial stage, natural conditions play a weak and indirect role, whereas policy incentives and socioeconomic growth are equally significant in driving agricultural space urbanization. In the eastern YREB, where urbanization is more saturated, the agricultural space urbanization is less constrained by natural factors, showing a high synergy with socioeconomic development. Conversely, in the central Yangtze River Economic Belt, policy influences surpass socioeconomic factors, whereas unfavorable natural conditions and agricultural development act as key drivers of agricultural space urbanization. This study suggests that enhancing agricultural space urbanization quality requires strengthening region-specific policies, providing targeted support for remote areas, rebalancing policy orientation in rapidly urbanizing regions, and establishing a comprehensive evaluation system to ensure policy rationality.</p>