An experiment with split-plot design which is water treatment as (3 levels: natural rainfall, increasing 30% of rainfall, and decreasing 30% of rainfall ) main treatment and nitrogen treatments(4 nitrogen levels: 0(N0), 30(N30), 50(N50) and 100(N100)kg/(hm~2·a) as sub-region in Stipa breviflora desert steppe, was conducted to understand the effects of simulated nitrogen deposition and rainfall changes on soil meso- and micro-fauna communities. Our results showed that soil fauna individual density in the surface soil was increased at first and then was decreased with nitrogen concentration increase in same water treatment.Soil meso- and micro-fauna communities individual density in W-N30treatment was significantly higher than that in other treatments (P<0.05), and group number decreased with nitrogen concentration. Rainfall reduction and excessive nitrogen application decreased the individual density of soil meso- and micro-fauna communities in the surface soil. Soil meso- and micro-fauna individual of the surface in Stipa breviflora desert steppe was significantly higher than that of subsurface soil. In addition, redundant analysis (RDA) showed the most obvious responsive to environmental factors soil fauna was the dominant and common groups in the study area.Soil meso- and micro-fauna communities individual density, rather than group number, was greatly influenced by soil pH, temperature, water content, organic matter and total C, total N and C/N ratio in short period. Soil fauna individual density in surface soil increased with nitrogen deposition increased under future projected climate change. However, soil fauna communities in surface soil were restricted when nitrogen reached threshold under different conditions.