Abstract：Objective：To investigate the effects of sophorindin on proliferation，migration and invasion of breast cancer cell BT549 and its molecular mechanism. Methods： The effects of different concentrations(1.0， 2.0， 4.0， 8.0 mg/mL) of sophorindin on proliferation，migration and invasion of breast cancer cell BT549 were detected by cell counting Kit(CCK- 8) and Transwell test. cells BT549 were divided into control(NC) group，sophoridine group，anti- miR- NC group，anti- miR- 345-5p group，sophoridine+anti-miR-NC group and sophoridine+anti-miR-345-5p group.The expression of miR-345-5p was detected by real- time fluorescence quantitative polymerase chain reaction(RT- qPCR) ， and the changes of cell viability ， migration and invasion were detected. The phosphorylated nuclear transcription factor(NF- κB) P65(p- p65) and phosphorylated NF- κB inhibitor protein(p- I κB α) were detected by Western blot. Results： After the intervention of sophoridine at different concentrations，the viability，migration and number of invasive cells of BT549 cells were significantly reduced. The concentration of sophoridine at 4.0 mg/mL was selected for follow-up experiment. Compared with NC group， the expression of miR- 345- 5p，p- p65 and p- IκBα in sophoridine group were significantly increased compared with antimiR- NC group，anti-miR-345-5p group increased cell viability，migration and invasion，p-p65 and p-IκBα compared with sophoridine+anti-miR-NC group， sophoridine+anti-miR-345-5p group increased cell viability， migration and invasion， p-p65 and p-IκBα expression increased(P＜0.05). Conclusion：Sophorindin can inhibit proliferation，migration and invasion of breast cancer cell BT549 through upregulation of miR- 345- 5p， and its mechanism may be related to inhibiting NF- κB signal pathway.