：The Huaihe River Eco-economic Belt (HREB) is a vital agricultural hub in China, encompassing 11% of the nation’s cultivated land and producing one-sixth of its total grain. Soil organic carbon (SOC), a key indicator of soil fertility, plays a vital role in maintaining soil quality and crop productivity. However, climate change and unresonable land management practices have significantly impacted soil carbon stocks in agricultural ecosystems, leading to soil degradation and reduced crop productivity. The study analyzed the spatial distribution and temporal dynamics of SOC stocks in the HREB from 1980 to 2020, identified the primairy drivers of SOC sequestration, and proposed targeted strategies to enhance carbon storage for sustainable agricultural development. The results showed that soil organic carbon stocks (SOCS) increased by 227.73 Tg over four decades in HREB, with an average sequestration rate of 220.30 kg C ha -1 yr -1, highlighting the significant carbon sink function. Regional SOCS exhibited a ”higher-south, lower-north” spatial pattern, with south-north soil organic carbon density (SOCD) differences of 0.70, 0.57, and 1.04 kg m -2 in 1980, 2010, and 2020, respectively. Soil pH, nitrogen fertilizer input, average annual temperature, and average annual rainfall are the primary explanatory variables influencing the annual variation of SOCD in the regions, with relative importance values of 18.46%, 10.67%, 10.37%, and 8.05%, respectively. Soil pH was the most critical determinant, affecting SOC stabilization through mineral interactions, microbial communities, and enzyme activities. Despite excessive nitrogen application accelerating SOC decomposition, it also enhanced carbon inputs via crop root exudates. Additionally, rising temperatures (+0.39°C per decade) and humid conditions promoted plant and microbial activity, enhancing SOC accumulation. Optimizing soil pH regulation and nitrogen management while adjusting to climate change is crucial for enhancing soil carbon sink capacity and guaranteeing sustainable agricultural production.