The increasing global atmospheric nitrogen (N) deposition has an important impact on soil respiration. Due to different sources of different components of soil respiration, there are different mechanisms for the responses to N additions. To investigate the effect of N addition on total soil respiration (RS_T), rhizospheric respiration (RS_R) and heterotrophic respiration (RS_H), one N addition experiment was conducted in a subtropical evergreen broad-leaved forest. Three N treatments (+0, +50, +150 kg N ha⁻¹ yr⁻¹) were added monthly to soil surface since April 2013. Soil respiration was measured monthly from May 2015 to April 2016. The results showed that the annual mean rate of RST was 1.92 ± 0.18 μmol CO₂ m⁻² s⁻¹ (7.3 ± 0.7 t C ha⁻¹ yr⁻¹), RS_H and RS_R contributed (75 ± 1) % and (25 ± 1) % to RS_T, respectively. Nitrogen addition significantly reduced RS_T by reducing RS_H and RS_R. Nitrogen addition decreased the RSR by reducing belowground carbon (C) allocation. RS_H decreased mainly due to the reduced microbes and soil organic matter (SOM) decomposition in root-free soil after N addition.