【Objective】Global climate change has had a huge impact on the carbon pool of terrestrial ecosystems, and the changes in average temperature and precipitation patterns pose severe challenges to the management of terrestrial carbon pools. This is especially serious in the Loess Plateau where the ecological environment is fragile. Therefore, understanding the changes of different fractions of soil organic carbon pool and the stability of this carbon pool under the background of the warming and humid climate of the Loess Plateau is of great significance. This will be of importance in the sustainable development of the carbon pool in fragile ecological areas and the evaluation of regional ecological benefits.【Method】In this study, natural abandoned grassland in the loess hilly region was taken as the research object. Soil warming and increased precipitation were artificially simulated and the changes in vegetation community, soil carbon fractions content and distribution, carbon pool stability index under warming (W), precipitation (P50%) and their interactions (WP50%) were analyzed. 【Result】The results showed that: (1) P50% significantly increased the vegetation Gleason richness index, W and WP50% significantly reduced the Gleason richness index (P < 0.05) and the leaf organic carbon content under the WP50% was significantly higher than the control treatment. Both P50% and WP50% treatments reduced the Shannon-wiener diversity index and pielou evenness index. (2) Soil organic carbon (SOC), acid hydrolyzable organic carbon (AHC), easily oxidizable carbon (EOC), dissolved organic carbon (DOC) content and their distribution ratio of the two sampling years under P50% were significantly higher than the control treatment. Also, warming based on P50% can further increase soil EOC, microbial biomass carbon (MBC) content and distribution ratio. However, only the soil MBC showed a significant difference compared with the control under W treatment. Recalcitrant organic carbon (ROC) presents an opposite trend to AHC. The correlation analysis showed that there was a significant correlation between soil total organic carbon and each active carbon fractions (P < 0.05). (3) The soil carbon pool activity (CA), carbon pool activity index (CAI), and carbon pool management index (CPMI) under WP50% treatment were higher than other treatments. The sensitivity index of AHC and MBC was relatively high under the treatment of climate change.【Conclusion】In summary, the total organic carbon, the content and distribution ratio of active fractions of organic carbon, and the stability of the carbon pool in abandoned grassland of the loess-hilly area will be significantly improved under background warming and humid climate. This will contribute to the healthy development of the carbon pool. From a sensitivity point of view, AHC and MBC can be used as early important indicators of changes in soil organic carbon under warm and humid climates in the future. This study provides a theoretical and scientific basis for research on climate change and carbon pool management in fragile ecological areas.