Soybean ［Glycine max （L.） Merr.］ can form a symbiotic relationship with rhizobia for biological nitrogen fixation. Brassinosteroid （BR） as an important hormone regulates plant growth and development and negatively affects soybean nodulation. The function of brassinosteroid receptor BRI1 in symbiotic nitrogen fixation remains unclear. Therefore， analysis of the characteristics and functions of GmBRI1 gene family members is crucial for revealing their roles in soybean growth and development. In this study， six GmBRI1 genes were identified in the soybean genome by bioinformatics methods. They were unevenly distributed on four chromosomes， encoding proteins with 1136 to 1211 amino acids， of which leucine was the most abundant. These proteins were acidic and stable proteins. Phylogenetic analysis divided the GmBRI1 gene family members into three subfamilies， with highly similar gene structures and conserved motifs within each subfamily. Synteny analysis indicated that the family expansion resulted from fragment duplication events. Promoter analysis revealed multiple cis-elements related to light， hormone， stress response and growth and development. The number of potential phosphorylation sites in GmBRI1 proteins ranged from 111 to 132. Protein interaction network prediction identified 19 interacting proteins and 9 directly binding proteins involved in BR signal transduction. The GmBRI1 family genes expressed in both roots and nodules， and four genes GmBRI1a， GmBRI1b， GmBRL1a and GmBRL1b were down-regulated after rhizobia infection. This study provided a new theoretical basis for the functional research of soybean GmBRI1 family genes， highlighting their response during the early stages of rhizobium infection， and advances our understanding of their functions and mechanisms in soybean symbiotic nodulation.