Abstract: Optimizing the land use spatial pattern of major agricultural production areas at the county level is of critical importance for implementing the national functional zoning strategy and ensuring food security. This paper constructs an optimization framework for the land use spatial pattern of major agricultural production areas, based on the four aspects of "scale-structure-layout-strategy." Taking Qixian County in Shanxi Province as an example, the optimization goals are defined as food security, ecological security, economic development, carbon reduction, and social security. The study couples the grey multi-objective model with the GeoSOS-FLUS model for optimization, and further divides the county into functional zones, proposing development strategies for each zone. The results are as follows: 1) Through structural optimization, by 2035, the area of arable land will remain at 38,320.6 hectares, ensuring food security; the area of forest land will increase to 17,172.4 hectares, enhancing carbon sequestration; grassland will decrease to 21,485.8 hectares, optimizing land use; the water area will increase to 159.5 hectares, improving ecological services; and construction land will expand to 8,214.7 hectares. The total economic output will increase by 1,097,676 million yuan compared to 2021. Net carbon emissions will be reduced by approximately 239,200 tons compared to the natural development trend, and 86,250 tons compared to 2021. Carbon intensity will decrease by 53.34% compared to 2021, and by 88.57% compared to 2005. These adjustments achieve multiple objectives in agricultural production, ecological protection, and economic development. 2) The GeoSOS-FLUS model layout simulation shows that the Kappa index reaches 0.870, with an overall accuracy of 0.910, indicating high precision and reliable results. After optimization, forest land is more concentrated and efficient, significantly improving carbon sequestration; the quality of arable land is enhanced, further ensuring food security. Construction land is more concentrated, promoting economic circulation. While safeguarding the functionality of major agricultural production areas, the optimized layout provides a solid spatial foundation for the region's sustainable development. 3) Based on the development potential of different townships, the county is divided into three zones: agricultural production, economic development, and carbon sequestration. The carbon sequestration zone aims to enhance carbon sequestration and protect ecosystems, relying on the establishment of ecological corridors and promoting ecological projects such as returning farmland to forest, grassland protection, and wetland restoration, while fostering low-carbon tourism and ecological agriculture. The economic development zone focuses on promoting the development of characteristic industry clusters, improving infrastructure, enhancing connectivity with the Taiyuan metropolitan area, and driving industrial restructuring and carbon reduction. The agricultural production zone prioritizes the protection of basic farmland and the improvement of arable land quality, develops characteristic agriculture, promotes the branding of Qixian pear, implements green and low-carbon agriculture, and builds modern agricultural industrial parks and rural infrastructure. This research focuses on optimizing the land use spatial pattern of major agricultural production areas at the county level, aiming to coordinate multiple objectives such as food security, economic development, carbon reduction, ecological security, and social security, and to achieve an organic integration of county functional zoning and multidimensional development. The differentiated development strategies proposed in this study provide clear guidance for local governments in formulating land use policies and territorial spatial planning. This research not only deepens the understanding of land use spatial optimization in functional counties but also offers valuable insights for optimizing other functional counties, and lays a solid foundation for agricultural modernization and the achievement of carbon neutrality goals.