[Objectives]  To investigate the soil animal diversity and community structure of saline-alkali soil in sunflower fields in Northern of Ningxia, and to reveal the relationship between soil animal diversity, community structure and soil factors over time in improved saline land. [Methods]  The relationship between biotic factors and abiotic factors has been an important issue in ecology, especially in restoration ecology. In order to reveal the mutual relationships between soil animals and soil environmental factors we conducted a field investigation to collect biotic data in saline-alkali sunflower fields. [Results]  Results showed that a total of 12 types of soil fauna, dominated by Collembola (60.67%) and Acarina (23.24%), were not significantly changed by the improvement of saline land. Diversity, Margalef richness, and uniformity also remained unchanged by the improvement of saline-alkali soil. [Conclusion]  Soil pH, basicity and salt were the limiting factors of soil fauna distribution. The number of soil animals was higher in lower salt environment. The presence of Collembola, soil pH, and total salt content were negatively correlated with soil moisture. The Acarina distribution was affected by these factors, but not significantly so. These results provide important information for the improvement of saline land.