[Objective] The impacts of Yellow River irrigation on physicochemical properties and microbial diversity of saline-alkali soils at Pingluo County， Ningxia Hui Autonomous Region were investigated， in order to provide scientific support for ecological remediation of saline-alkali soils in the region. [Methods] Soil samples from paddy fields at Pingluo County， with different rice planting years （1， 5， 10， and 16 years） during the flooding period （July） and the draining period （October） were analyzed to characterize soil physicochemical properties and bacterial diversity in the salinization of different rice planting years in the two periods by using Illumina Hiseq high throughput sequencing technology. [Results] Soil moisture content， electrical conductivity， soil organic carbon content and total nitrogen content increased significantly with increasing years of rice cultivation. Electrical conductivity， soil organic carbon and total nitrogen increased significantly after 5 years of rice cultivation. The pH value， nitrate nitrogen content and soluble organic nitrogen content decreased significantly with an increasing number of rice cultivation years. The lowest soil pH value after 16 years of rice cultivation in the drainage was 2.66% lower than that in the soil after one year of rice cultivation. The microbial biomass carbon and nitrogen were significantly higher in the soil with rice cultivation for the 16-years paddy soil in the drainage than in the 1-year paddy soil with rice cultivation by 36.28% and 36.59% respectively. Years of rice cultivation had a significant effect on bacterial community diversity and structure. The Chao1 index was 43.99% higher in the soil with rice planted for 16 years during the submerged period than in the soil with rice cultivation for one year. During the submerged period， the relative abundance of Gemmatimonadetes and Spirochaetes increased by 27.46% and 150.00% respectively， in the 10-year paddy soil. The relative abundances of Actinobacteria， Firmicutes and Cyanobacteria significantly decreased by 44.50%， 66.23% and 87.50% respectively， in the 5-year paddy soil. During the drainage period， the relative abundances of Fibrobacteres and Spirochaetes increased by 287.50% and 314.29% respectively， in the 5-year paddy soil. The relative abundances of Chloroflexi and Chlorobi increased by 46.35% and 370.97% respectively， in the 10-year paddy soil. The relative abundances of Actinobacteria， Nitrospirae and Armatimonadetes significantly decreased by 48.10%， 55.34% and 65.85% respectively， in the 5-year paddy soil. At the genus level， the relative abundances of Pseudanabaenaceae and Comamonadaceae decreased significantly by 96.89% and 56.60% respectively， in the 5-year cultivated soil during the submerged period. The relative abundances of Caldilineaceae and Desulfobulbaceae significantly increased by 64.86% and 305.26% respectively， in the 10-year cultivation soil during the submerged period. Redundancy and Pearson correlation analyses showed that soil conductivity， total nitrogen， nitrate nitrogen， ammonium nitrogen， dissolved organic carbon and dissolved organic nitrogen were the key environmental factors affecting bacterial community structure in saline paddy soil. [Conclusion] Significant changes in the soil bacterial communities and physicochemical properties were observed with an increase in the number of rice cultivation years， and the soil habitat showed an improving trend.