Bioinformatics analysis， spatiotemporal expression localization， GUS staining localization and gene silencing were used to study the mechanism of SBT family proteins in the soybean-rhizobia symbiosis to investigate the function of the GmSBT1 gene in symbiotic nitrogen fixation between rhizobia and host plants. The results showed that the GmSBT1 gene was specifically induced by rhizobia and only expressed at high levels in the nodules， possibly functioned in the rhizobia cortex and bacterial cells. RNA interference significantly reduced the fresh weight， nodule weight， and nitrogenase activity aboveground. It is indicated that the GmSBT1 protein plays an important role in the formation and development of nodules， and the nitrogen fixation in nodules as well.