Objective：To investigate the role and mechanism of chromosomal region maintenance 1 (CRM1) inhibitor sulforaphene (LFS-01) in killing triple negative breast cancer (TNBC) cells by inhibiting signal transducer and activator of transcription 3 (STAT3) signaling pathways. Methods: Whether LFS-01 could combine with the NES pocket of CRM1 was verified by molecular dynamics simulation techniques. The killing activity of LFS-01 on four different breast cancer cell lines was detected by CCK-8 method. TNBC MDA-MB-468 and MDA-MB-231 cells were treated with different concentrations of LFS-01, and the intracellular localization of CRM1 cargo protein STAT3 and protein with NES sequence was detected by immunofluorescence; WB was used to detect the effect of LFS-01 on the expression of STAT-3 signaling pathway and its downstream proteins; WB, cellular immunofluorescence and transmission electron microscopy were adopted to detect the occurrence of autophagy; the effect of LFS-01 on cell cycle and apoptosis was detected by flow cytometry. Results: Molecular dynamics simulations showed that LFS-01 can bind to the NES pocket of CRM1, indicating that it may structurally affect the latter's protein transport function. LFS-01 could specifically kill TNBC MDA-MB-468 and MDA-MB-231 cells. STAT3 and NES-tagged proteins were mainly blocked in the nucleus of TNBC cells after the treatment with 10 μmol/L LFS-01, while they were evenly distributed in the cytoplasm in the control group. The expressions of phosphorylated STAT3 protein, Bcl-xL and Cylin D1 were decreased in MDA-MB-468 and MDA-MB-231 cells with the increase of LFS-01 dose and the prolongation of treatment time; the expression of autophagy marker protein LC3B increased, and highdensity, multi-layered autophagosomes appeared at the same time; cell cycle arrest was observed in S phase and apoptosis rate was significantly increased (P<0.05 or P<0.01). Conclusion: LFS-01 blocks the export of CRM1 carrier protein, thereby inhibiting the activation of STAT3 signaling pathway and promoting autophagy, cell cycle arrest and apoptosis in TNBC MDA-MB-468 and MDAMB-231 cells.