To understand the effect of global climate change on soil fauna in Inner Mongolian desert steppe,we studied the effect of warming,N addition, their interaction of the warming and the N addition and control on soil mesofauna community in the Stipa breviflora desert steppe of Siziwang Banner. The results showed that soil fauna in various groups in desert steppe responsed to warming and N addition differently: 1) Warming significantly reduced the taxnon of Coleoptera larvae in Stipa breviflora desert steppe,however,had no significant effect on the other soil fauna; N addition significantly increased the density of Collembola and the density and group number of Mesosigmata,however,has no significant effect on the other soil fauna; The interaction of the warming and the N addition significantly reduced density and group number of Coleoptera larvae,however,has no significant effect on the other soil fauna. 2) Vertical distribution of soil fauna in Stipa breviflora desert steppe had obvious surface assembly: in the interaction of the warming and the N addition, the density in 0-10cm was significantly higher than 10-20cm. In N addition treatment,the density and group number in 0-10cm was significantly higher than 10-20cm. Our study found that climate warming and nitrogen deposition may affect soil fauna community composition and vertical structure.