Land use change is an important factor in atmospheric carbon emissions. Most of the existing studies focus on modeling the land use pattern for a certain period of time in the future and calculating and analyzing carbon emissions. However, few studies have optimized the spatial pattern of land use from the perspective of the impact of carbon emission constraints on land use structure. Therefore, in this study, the effects of land use change on carbon emissions from 1990 to 2020 were modeled using a carbon flow model for Sanmenxia, Henan, China, as an example. Then, the land use carbon emission function under the low carbon target was constructed, and the differential evolution (DE) algorithm was used to obtain the optimized land use quantity structure. Finally, the PLUS model was used to predict the optimal spatial configuration of land use patterns to minimize carbon emissions. The study produced three major results. (1) From 1990 to 2020, the structural change of land use in Sanmenxia mainly occurred between cultivated land, forest land, grassland and construction land. During this period of land use change, the carbon emissions from construction land first increased and then decreased, but despite the decrease, carbon emissions still exceeded carbon sinks, and the carbon metabolism of land use was still far from equilibrium. (2) Between 2010 and 2020, the area of cultivated land began to decrease, and the area of forest land rapidly increased, and land-use-related carbon emissions showed negative growth. This showed that the structural adjustment of energy consumption in Sanmenxia during the period decreased carbon emissions in comparison with the previous period. (3) A comparison of predicted optimized land use patterns with land use patterns in an as-is development scenario showed a decrease in construction land area of 23.05 km² in 2030 with a steady increase in forest land area and a decrease in total carbon emission of 20.43 t. The newly converted construction land in the optimized land use pattern was concentrated in the ribbon-clustered towns built during urban expansion along the Shaanling basin of the Yellow River and the Mianchi–Yima industrial development area.

The expansion of built-up areas has a significant impact on the spatial distribution of land use within a given region. The accurate identification of appropriate regions for the expansion of builtup land holds significant importance in shaping the future distribution of land use patterns. Using Sanmenxia City in Henan Province as a case study, this analysis focuses on obstacle factors such as the suitability of land resources, ecological service value, and ecological security. A built-up land expansion suitability evaluation index system was developed, and the weights were determined using entropy gray correlation analysis. We employed the weighted average comprehensive index model to examine the attributes associated with the suitability of built-up land expansion within the designated study region. Subsequently, the PLUS model was employed to simulate the prospective land utilization within the study area, with the suitability of built-up land expansion as a constraint. The findings of this study will serve as a fundamental framework for informing decision-making processes pertaining to land space planning, ecological construction, and urban development in Sanmenxia City.