To better understand the responses of soil carbon and nitrogen to the nitrogen addition, this paper revealed the response processes and mechanisms of soil carbon and nitrogen to exogenous nitrogen addition through a short-term simulated nitrogen deposition experiment in artificial Pinus tabulaeformis Carrière plantation in Ziwuling Mountain of the Loess Plateau. From 2015 to 2016, four nitrogen addition levels, including control (0 kg/(hm²·a), N0), low nitrogen (50 kg/(hm²·a), N50), medium nitrogen (100 kg/(hm²·a), N100), and high nitrogen (200 kg/(hm²·a), N200), were set up to study the responses of soil organic carbon(SOC), total nitrogen (TN) and soil carbon and nitrogen storage (C_S and N_S) in different soil depths to the simulated addition nitrogen. The results showed that soil layer had significantly influence on SOC, TN, C_S and N_S. SOC, TN, C_S and N_S in the surface layer were significantly higher than those in the deeper soil layers. Nitrogen addition level had no significant impact on the SOC and C_S, while significantly affected the TN and N_S. In addition, SOC, TN, C_S and N_S, and C_S/N_S were significantly affected by the carbon nitrogen ratio (C/N) of belowground biomass. Therefore, short-term nitrogen addition had no significant influence on soil carbon, but it could significantly affect soil nitrogen, and C/N of belowground biomass was the important factor affecting soil carbon and nitrogen.