In order to analyze the effect of nitrogen deposition on the composition and stability of soil carbon pool, Pinus tabuliforrnis Carr. was selected as the research object in this study. Nitrogen addition simulating nitrogen deposition was used to analyze the effects of short-term nitrogen deposition. The results showed that the SOC,the high activity component (C_1),the middle activity component (C_2) in the upper soil increased with the increase of the nitrogen contents,and the content of stability component (C_4) firstly increased and then decreased,reaching to the maximum value at N_3,and had little effect on the SOC and its components of the deep soil. Nitrogen addition has little effect on the distribution ratio of different carbon components in total organic carbon and the activity coefficient of soil carbon pool,and C_4 has the largest proportion among the four components,reaching to 74.3%~87.3%. From the point of view of the stability of soil carbon pool,this study analyzed the effect of nitrogen addition on the carbon pool composition in the forest soils in the loess hilly region,which is conducive to the understanding of the impact of future global changes on soil carbon pool processes.