The ecosystem respiration (R-e) is a key process of carbon from soil into atmosphere. It is highly sensitive to the changes in precipitation and nitrogen input (N-i), and plays a significant role in influencing warming. However, how annual precipitation and N-i affect the R-e and its temperature sensitivity (Q(10)) in arid ecosystems remains unclear. Therefore, an in-stiu N-i manipulation experiment was conducted during both a humid year and a drought year in the desert steppe of western China. The results showed that R-e exhibited an distinct unimodal trend in a humid year but not in a drought year, leading to marked different in Q(10) in 2 years. The Q(10) was higher in a humid year (1.9) rather than that in a drought year (1.1). The effect of N-i on R-e was variable, exhibiting both stimulatory and inhibitory effects, which overall resulted in no significant impact on R-e. N-i exerted a similar stimulatory effect in a humid year (31.0% +/- 7.2%) and in a drought year (34.7% +/- 6.1%), with an the increasing trend observed with higher N-i levels. Meanwhile, the Q(10) was also showed an increasing trend with the with higher N-i in a humid year (except at 1 g N m(-2) year(-1)). In contrast, during the drought year, low N-i level (< 3 g N m(-2) year(-1)) reduced Q(10), whereas much higher N-i level (> 6 g N m(-2) year(-1)) increased Q(10). Soil moisture exerted a threshold-dependent regulatory effect on R-e. In the humid year, R-e initially increased and then decreased with rising soil moisture, whereas in the drought year, Re showed a significant declining trend as soil moisture increased. The results from the structural equation model showed that R-e was primarily regulated by plant root biomass in a humid year, but by soil temperature in the drought year, and the annual precipitation exerted the most of important indirect effect on R-e, primarily by influencing soil moisture, root biomass and soil temperature. In conclusion, R-e and its Q(10) in this desert steppe was more sensitive to inter-annual precipitation variability than to N-i. In a humid year R-e mainly mediated by root biomass, whereas in a drought year, it was largely governed by changes in soil moisture and temperature. These findings provided critical insights for the development of R-e model in the Eurasian inland desert steppe.