【Objective】 Soil salinization affects the quality of arable land and threatens the sustainable development of agriculture. As an important indicator of soil environment, soil microbes play important roles in driving soil nutrient cycling and maintaining ecosystem productivity. Therefore, deciphering the response of microbial communities and their potential functions to the degrees of soil salinization and land use type is of great significance for understanding the elemental cycling processes and interactions with plants in a saline-affected agroecosystem.【Method】 In this study, we explored the composition and potential functions of prokaryotic communities and their environmental drivers in saline soils from farmlands and wastelands with different salinization degrees, by combining prokaryotic high-throughput sequencing and soil physicochemical analysis methods in a typical saline area of Hetao Irrigation District of China. 【Result】 Compared with wastelands, the farmlands exhibited a lower soil salinity but a higher content of soil organic matter (SOM) (P < 0.05). In farmlands with different salinity levels, mild saline soil had a significantly higher yield of sunflower than the moderate and severe saline soils. Meanwhile, the saline soils in farmland exhibited a higher prokaryotic α diversity than that in the salinized wasteland, with a large number of unique ASVs (Amplicon sequence variants). The prokaryotic α diversity indexes were positively associated with SOM contents but negatively correlated with soil pH, EC, moisture and bulk density. Non-metric multidimensional scaling (NMDS) analysis based on the β diversity of prokaryotes further indicated that the prokaryotic community was mainly differentiated between farmland and wasteland, followed by the soil salinity level in each land use type. Specifically, the prokaryotic community was dominantly driven by environmental factors including EC, pH and SOM, as suggested by canonical correlation analysis (CCA) and Mantel test. Moreover, the phylum including Acidobacteriota, Chloroflexi, Planctomycetota, Crenarchaeota, and Myxococcota in farmlands showed significantly higher abundance than wastelands, whereas Halobacterota and Bacteroidota showed an opposite trend, with Halobacterota only detectable in wastelands and relative abundance ranging from 10.13% to 39.41%. Through predicting the potential functions of the prokaryotic community, we found that there were high abundances of nitrogen cycling-related microbes like Nitrososphaeraceae and Nitrososmonadaceae, and potential plant growth-promoting bacteria including Nocardioidaceae and Sphingomonadaceae in salinized farmlands. By contrast, the salinized wasteland enriched prokaryotic groups with potential hydrocarbon decomposition function.【Conclusion】 Our study indicates strong selection effects of different land use types on prokaryotic communities in salinized soil of Hetao Irrigation District, which has important implications for clarifying the feedback between prokaryotic community and physicochemical properties of saline soils, as well as revealing the synergy effect among soil-plant-microorganism for soil nutrient turnover and agricultural sustainability.