Abstract: This study investigates the spatial distribution characteristics, temporal changes, and influencing factors of total carbon density, organic carbon density, and reserves in the farmland soils in Luoyang City based on repeated sampling data from multi-purpose regional geochemical survey points over different periods. The results indicate that in 2005, the topsoils in the multi-purpose survey area exhibited an average total carbon content of 1.57%, an average total carbon density of 44.74 t/hm², an average organic carbon content of 1.12%, and an average organic carbon density of 34.27 t/hm². With annual average increases in the total carbon density and organic carbon density of 0.709 t/hm² and 6.643 t/hm², respectively, this year witnessed increases in the total carbon and organic carbon of 41.73 kg/(hm²·a) and 390.75 kg/(hm²·a), respectively. The respective reserves of total carbon and organic carbon were 12.511 3 million tons and 8.879 59 million tons, with respective increases of 198.28 thousand tons and 1.857 8 million tons. In 2018, the topsoils in the multi-purpose survey area displayed an average total carbon content of 1.18%, an average total carbon density of 34.27 t/hm², an average organic carbon content of 1.07%, and an average organic carbon density of 30.94 t/hm². With annual average increases in the total carbon density and organic carbon density of 9.642 t/hm² and 4.727 t/hm², respectively, this year witnessed increases in the total carbon and organic carbon of -2,410.5 kg/(hm²·a) and 1,181.75 kg/(hm²·a), respectively. The respective reserves of total carbon and organic carbon were 1.963 5 million tons and 1.772 61 million tons. The total carbon reserves in topsoils in the whole study area were 14.474 81 million tons, including organic carbon reserves of 10.652 2 million tons. The total carbon reserves decreased by 552.41 thousand tons, while the organic carbon reserve increased by 270.82 thousand tons. Overall, the study area experienced a total carbon decrease of 354.13 thousand tons and an increase in the organic carbon reserves of 2.128 62 million tons. The total carbon showed significant positive correlations with the contents of organic carbon, CaO, MgO, N, and P, the organic carbon displayed significant positive correlations with the contents of total carbon, N, and P, and there was a significant positive correlation between pH and the CaO content. Fertilization led to an increase in the organic carbon and total carbon contents in farmland soils, with total carbon being significantly affected by the CaO content. In the carbonate areas, alkaline soil environments exhibited carbon sink characteristics. In the southern regions with acidified soil environments, the decomposition of carbonates in soils led to carbon loss and reduced calcium content. The results of this study provide important scientific evidence for research on peak carbon dioxide emissions and carbon neutrality of Luoyang City.