[Objective] The effects of different stand types on soil carbon pools and soil carbon stability in the Geqiugou watershed in Ordos City of Inner Mongolia Autonomous Region were analyzed in order to provide a theoretical basis for determining the mechanism of soil carbon sequestration, optimizing soil management and plant breeding measures in the Geqiugou watershed, and realizing soil carbon sequestration emission reduction and fertility improvement in the Geqiugou watershed. [Methods] Eight-year-old plantations of Pinus sylvestris, Carga cathayensis, Pinus tabulaeformis, Poplar-Caragana mixed forest, Chinese pine and arborvitae mixed forest, sea buckthorn and mountain apricot mixed forest, and a control (CK) treatment were used as the research objects in the Geqiugou watershed from 2013 to 2021. The contents of total organic carbon (TOC), resistant organic carbon (ROC), easily oxidizable organic carbon (EOC), microbial biomass carbon (MBC), and soil carbon storage in different stand types at different soil depths were determined to study the effects of plantations on soil carbon pools, and to determine the relationship between different stand types and soil carbon stability. [Results] Compared with the CK treatment, the contents of TOC, ROC, EOC, MBC, and soil carbon storage in the 0—20 cm and 20—40 cm soil layers increased by 9.46%—51.24%, 1.76%—44.89%, 16.48%—44.26%, 9.03%—64.84%, and 10.61%—55.52%, respectively. [Conclusion] Plantations of different stand types can increase soil TOC, ROC, EOC, MBC contents and soil carbon storage in the 0—20 cm and 20—40 cm soil layers. The soil TOC, EOC, MBC contents and soil carbon storage decreased with increasing soil depth, and soil ROC content increased with soil layers. The soil carbon pool index for each stand type in the 0—20 cm and 20—40 cm soil layers was greater than that of the CK treatment. P. sylvestris, C. cathayensis, and mixed sea buckthorn and mountain apricot were more conducive to soil carbon sequestration in the Geqiugou watershed.