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Rhizobium seed dressing is one of the effective measures to improve the nitrogen fixation efficiency of plants. Our study investigated the effects of rhizobium seed dressing on the structure and diversity of soil microbial community in typical grass-legume mixtures in alpine regions, aiming to provide a theoretical basis for the application in forage production. Taking the mixed sowing of Medicago sativa cv.‘Beilin201’, Elymus sibiricus L.cv.‘Chuancao No.2’, and Elynus nutans Griseb.cv.‘Aba’as the research object, 2 treatments of rhizobium seed dressing and no seed dressing were set. The bulk and rhizosphere soil were collected, and the prokaryotic biodiversity and community structure were analyzed based on 16S rRNA gene high-throughput sequencing technology, the functional prediction was calculated by FAPROTAX tools and the classification and changes of prokaryotes microbial high-level phenotypes were compared by BugBase analysis. A total of 8 814 OTUs were detected from 32 soil samples, belonging to 3 577 genera in 6 phyla, while the dominant phyla were Actinobacteria (26.11%-46.20%) and Proteobacteria(20.61%-32.91%) . Rhizobium seed dressing changed prokaryotic community structure and decreased diversity(Observed_richness, Shannon index, and inverse Simpson index) , but increased the abundance of digestion and denitrification taxa. The population belonging to aerobic, anaerobic, facultative anaerobic, gram-negative, and gram-positive prokaryotes in the rhizosphere soil of Gramineae increased after seed dressing, while the results of Legumes were the opposite. After seed dressing, the abundance of nifH gene in the legume rhizosphere significantly increased. In summary, seed dressing reduced the α-diversity of community, changed the structural composition, but increased the relative abundances of digesting and denitrifying populations, and increased the abundance of nifH genes. This study provides a scientific basis for the cultivation of rhizobia seed dressing in the grass-legume mixtures. [ABSTRACT FROM AUTHOR]