【Objective】In order to explore the diversity of seed-borne bacteria of oat and their growth promoting functions.【Method】9 seed-borne bacteria of oat cultivars were isolated and purified by traditional culture methods,and their functions of nitrogen fixation,phosphorus solubilization,IAA production and cellulose decomposition were qualitatively analyzed.【Result】A total of 34 bacterial isolates were isolated. Combined with their morphological characteristics and 16S rDNA analysis,the isolated bacteria belonged to 4 phyla and 19 genera of prokaryotes,in which Firmicutes was the dominant phyla for 56. 00%. The dominant genus was Bacillus sp. ,accounting for 41. 18%. 34 strains of oat seed bacteria all had different growth‐promoting functions. It belonged to the Bacillus sp. , Escherichia sp. ,Pseudomonas sp. ,Shigella sp. ,and Atlantibacter sp. 9 strains had the functions of nitrogen fixation, phosphorus solubilization,indole-acetic acid production and cellulose decomposition.【Conclusion】A total of bacterial 34 isolates were isolated in this experiment,all of which had different growth-promoting functions. Among them,9 strains had the functions of nitrogen fixation,phosphorus solubilization,indoleacetic acid production and cellulose decomposition. Shigella sp. LFt4 had the strongest comprehensive ability.