Studying the changes in soil microbial community structure and nitrogen metabolism in the process of vegetation restoration is an important part for better understanding the biogeochemical processes in terrestrial ecosystems. However, there are very few reports on the functional potential of soil microorganisms after planting artificial vegetation in arid deserts. We selected Haloxylon ammodendron plantations along an age sequence (3-, 6-,11-, 19-, 28-, and 46-years) for research, sampled surface soil (0-10 cm) under the canopy, and took the moving sandy land (Ms) as the control in an oasis-desert ecotone in northwestern China. We used high-throughput sequencing to explore the responses of soil bacterial diversity, structure, nitrogen metabolism, and functional genes to the restoration of H. ammodendron, and to investigate the key driving factors of soil bacterial community structure change. The results showed that Actinobacteriota and Proteobacteria were the main dominant phyla in all plots. Shannon diversity index increased significantly with plantation ages (P < 0.05), indicating that the establishment of H. ammodendron plantations improved the soil bacterial diversity. The Chao richness indices tended to increase with the restoration of vegetation. Hierarchical clustering analysis showed that soil bacterial communities in different plantation ages were divided into three groups, and bacterial communities from the same revegetation site were grouped together. Non-metric multidimensional scaling (NMDS) analysis indicated that the establishment of H. ammodendron plantations on moving sandy land significantly changed the structure of soil bacterial communities (P < 0.01). Spearman correlation analysis showed that soil organic carbon (SOC), moisture content (SM), available phosphorus (AP), and available potassium (AK) significantly affected the structure of bacterial communities and showed a significant positive correlation (P < 0.05). Other environmental factors like electrical conductivity, total carbon, and available nitrogen had no significant effect on soil bacterial community structure. Assimilatory and dissimilatory nitrate reductions were the main parts of nitrogen metabolism. The predicted proportions of hydroxylamine oxidase (hao), reductase (hcp), and ammonia monooxygenase (amo) associated with nitrification were low, especially in the moving sandy land, with an average abundance of 8.9×10^-5%. The abundance of nitrate-reduction genes (NRG) was 17.5-126.9 times that of ammonia-oxidization genes (AOG), indicating that the reaction rate of denitrification was faster than that of nitrification. NRG/AOG decreased with plantation ages, indicating that the growth of H. ammodendron contributed to the accumulation of soil nitrogen. Our study provides an overview of soil bacterial community during the restoration of H. ammodendron and insights into the critical roles of functional genes in the nitrogen cycle. The findings might improve better understanding of plant-soil interactions in arid desert ecosystem restoration.