Conducting territorial space quantity structure prediction and layout optimization under the shared socio-economic pathways (SSPs) contributes significantly to revealing the intricate and multifaceted impact that future human activities may exert on natural environment systems. The Yangtze River Economic Belt, stretching across the eastern, central, and western regions of China, encompasses economic and population aggregates that collectively account for more than 40% of the nation's total. Positioned as the primary battleground within the national development framework, it serves as the linchpin for prioritizing ecological preservation and fostering green development, thereby spearheading the trajectory towards high-quality economic growth. This study is anchored upon three scenario parameters, namely SSP₁, SSP₂, and SSP₄, within the shared socio-economic pathways. Utilizing advanced methodologies such as Markov models and multi-objective linear programming, the research endeavors to forecast the territorial space quantity structure of the Yangtze River Economic Belt spanning from 2030 to 2060, offering invaluable insights into future spatial dynamics and developmental trajectories. Employing dynamic optimization methods, this study meticulously simulates territory space patterns for typical years under various scenarios, providing a comprehensive understanding of their dynamics. Subsequently, it conducts a thorough analysis of the trend characteristics shaping the evolution of territory space quantity structure and its intricate patterns, shedding light on future developmental trajectories and spatial dynamics within the Yangtze River Economic Belt. The results indicate that: (1) Under the three scenarios, the proportion of forest territory space is highest in the Yangtze River Economic Belt in 2030 and 2060, followed by arable territory space, grass territory space, and construction territory space. Water space and unused space have relatively smaller proportions. (2) From 2030 to 2060, the outgoing areas with significant proportions in all three scenarios are construction territory space, forest territory space, and arable territory space. The incoming areas with substantial proportions are arable territory space and forest territory space. (3) Under the SSP₁ and SSP₄ scenarios, there is a significant concentration of construction territory space in the future, with a noticeable decrease in arable territory space in the river valley plains of the upper reaches of the Yangtze. In the SSP₂ scenario, the distribution of newly added construction territory space is more dispersed. The research findings, elucidating the nuanced dynamics of territory space quantity structure and patterns within the Yangtze River Economic Belt, can be instrumental in guiding policymakers and stakeholders towards informed decision-making processes for optimizing and allocating territory space, thereby fostering sustainable development and ecological preservation in the region.