Abstract: As a key ecological conservation initiative, the Grain for Green Program (hereinafter referred to as the "Program") has yet to undergo a quantitative analysis of the regionally differentiated ecological effects and trade-off relationships resulting from its implementation.This study integrates the FLUS-InVEST model to assess the Program’s effectiveness and ecological benefits in the Yangtze River Economic Belt.This study systematically reveals the inter-regional gradient differences and trade-offs in ecosystem service values across the upper, middle, and lower reaches of the basin, while also simulating the ecological benefits of the Program under various future scenarios.The results showed that: (1) From 2000 to 2020, the total area converted under the Program across the entire region reached 144×105  km2, presenting a gradient decreasing pattern in the upper reaches (021×105  km2), middle reaches (012×105  km2), and lower reaches (004×105  km2).The urbanization process, to a certain extent, constrained the effectiveness of the Program implementation, resulting in a reduction of forest land area in the middle and lower reaches by 002×105  km2 and 001×105  km2, respectively, compared with the initial stage of the Program.(2) The Program led to both synergistic and trade-off relationships among inter-regional ecosystem services: carbon storage in the upper reaches increased by 376 million tons, and soil retention in the middle reaches rose by 624 million tons.However, the grain yield in the lower reaches (-31199 million tons) and the habitat quality index value (-025) both decreased significantly.(3) Scenario simulations indicated that under the ecology-priority scenario (2040), the total value of ecosystem services increased by 520% compared with that in 2020, which was superior to the natural development scenario (-131%) and the slope-oriented scenario (-3241%).The total values in the upper, middle, and lower reaches increased by 022, 002, and 001, respectively.In the future, efforts should be made to further consolidate the carbon sink advantages in the upper reaches of the Yangtze River Economic Belt, strengthen soil and water conservation in the middle reaches, and restore grain production capacity in the lower reaches, so as to realize inter-regional complementary advantages and maximize the overall benefits