Abstract: The hydro-fluctuation zone of river wetlands is a typical ecological transition zone characterized by dynamic nutrient cycling and microbial functional shifts. As a representative sandy river wetland, Ningxia Huangshagudu National Wetland Park has received limited research attention regarding microbial diversity in its hydro-fluctuation zone. In August 2022, we investigated the microbial diversity in the hydro-fluctuation zone of the sandy river wetland at Huangshagudu Wetland Park, Ningxia. These regions were classified based on water conditions into the arid region (D), near-water area (NT), dry-wet interlacing area (DW), and flooded area (W). The Illumina MiSeq high-throughput sequencing was employed to analyze the bacterial community structure and diversity characteristics, and to explore the co-evolution and influencing factors of soil physicochemical properties and bacterial community structures and functions in the hydro-fluctuation zone.The results indicated that soil bacteria in the study area comprised 42 phyla, 120 classes, 180 orders, 231 families, 333 genera, and 118 species. The predominant bacterial groups detected across different water regions were Proteobacteria, Actinobacteria, Firmicutes, Acidobacteria, and Chloroflexi. Proteobacteria and Actinobacteria were present in all four regions, yet significant differences in abundances were observed among them. Arthrobacter was the most dominant genus in the D, DW, and W regions, while Bacillus dominated in the NT region. Among the top 10 distinct floras in the four regions, Bacteroidota exhibited the most notable change in relative abundance. At the genus level, Balneimonas, Rubellimicrobium, and Rhodocytophaga showed the most significant variations in relative abundance. Although the near-water area had the highest soil nutrient content under different water conditions, its bacterial community structure and species composition were simpler compared to other areas. Bacterial functions across different moisture conditions were rich, with high activity in metabolism, genetic information processing, and environmental information processing.Water has an important influence on the metabolic function of soil bacterial communities in sandy river wetlands.The soil bacterial community structure in sandy river wetland is sensitive to the response of water changes, and the relative abundance of some bacteria has changed significantly, and the water conditions mainly affect the microorganisms under Proteobacteria in wetlands.Soil volumetric water content, soil organic matter, pH, available nitrogen, and electrical conductivity are the main influencing factors affecting the soil bacterial community structure, so the results can provide an important reference for the protection and sustainable utilization of sandy river wetlands.