Increasing nitrogen (N) deposition is significantly affecting the carbon cycle in forest ecosystems. However, it is not clear how N deposition affects the content of labile organic carbon in soil aggregates, which restricts our understanding of the soil carbon cycle and the development of the carbon cycle model. This study was conducted in an artificial Pinus tabulaeformis forest and simulated N deposition for nearly 2 years. Three N treatments, namely, N3 (3 g N m^-2 a^-1), N6 (6 g N m^-2 a^-1), and N9 (9 g N m^-2 a^-1), and a control treatment with no N added were applied, and each was replicated six times. Three labile organic carbon in soil aggregates were measured. There was no significant effect of short-term N addition on surface soil aggregates, while soil organic carbon was dramatically affected by N addition. Soil organic carbon content in the 0-10 cm soil layer was higher in the three N addition treatments and was highest in the N6 treatment. Additionally, the change in organic carbon content in macro-and micro-aggregates generally followed the pattern of soil organic carbon, and moderately, highly labile organic carbon also followed. In soil aggregates, the amount of highly labile carbon was greatest, then moderately labile carbon, and the content of minimally labile carbon was lowest. Compared to three labile organic carbon of CK treatment, the amount of minimally, moderately, and highly labile organic carbon in the N6 treatment increased by 115.06%, 178.73%, and 79.61% in macro-aggregate, respectively. And the amount of three labile organic carbons in the micro-aggregate increased by 32.84%, 166.79%, and 62.05%, respectively. Among the three labile organic carbon categories, the change of moderately active organic carbon in the macro-and micro-aggregates was highest, which indicated that the moderately active organic carbon in soil aggregates was the most sensitive to short-term N addition. The results showed that short-term N addition affected surface soil organic carbon content by changing the amount of moderately labile organic carbon in the surface soil macro-and micro-aggregates. The results of a principal components analysis showed that soil total N and pH were affected by short-term N addition and it also caused a change in soil texture and total P. The changes of soil physical and chemical properties may result in an increase in root biomass and litter decomposition which brought a significantly change on active organic carbon content in surface soil aggregates.