In order to understand the effect of nitrogen deposition on the community structure of meso-micro soil fauna in meadow steppe, a simulated nitrogen deposition experiment was conducted in 2010 in Baikal meadow steppe, Ewenke Banner, Hulunbuir City of Inner Mongolia. The changes of soil fauna community structure and diversity and their relationship with environmental factors were studied under eight nitrogen deposition gradients N0 (control), N15, N30, N50, N100, N150, N200 and N300. Soil fauna were collected in 2019 in the grass turning green period (May), the growing period (August) and the withering period (the end of September). The results showed that meso-micro soil fauna had obvious surface aggregation characteristics, but soil fauna community tended to migrate to deep soil with the increase of nitrogen application. The good hydrothermal conditions in the growing period of vegetation in the experimental area are more suitable for the development of meso-micro soil fauna community. The individual numbers, group numbers and diversity indexes of soil fauna under N200 and N300 treatments were significantly higher than those of the control and lower nitrogen deposition treatments (P<0.05). According to the distribution of dominant groups and common groups of soil fauna, nitrogen gradient was divided into three groups by principal component analysis (PCA), one group treated with N0-N150, N200 and N300 respectively. Redundancy analysis (RDA) showed that available potassium, total nitrogen, nitrate nitrogen, pH, organic matter and water content were the main environmental factors affecting the distribution of soil fauna communities. In general, nitrogen deposition can promote the development of soil fauna community but with a threshold of N 200 kg/(hm²·a) in this study.