OBJECTIVE:To investigate the efficacy of Biejia(Carapax Trionycis) and Ezhu(Rhizoma Curcumae Phaeocaulis) couplet medicine on epithelial-mesenchymal transition(EMT), invasion and migration of MDA-MB-231 triple negative breast cancer(TNBC)cells based on PI3K/Akt/mTOR signaling pathway.METHODS:MDA-MB-231 cells were treated with different medicated serum as Biejia-, Ezhu-,Biejia-Ezhu(BJ-, EZ-, BJ-EZ-) groups, intervened with no drug rat serum and paclitaxel with final concentration of 33 nM(IC_(50)) as negative and positive control(NC and PC) groups. CCK-8 assay,scratch test, and Transwell assay were used to examine cell proliferation, invasion, and migration.The expression of E-cadherin, N-cadherin, Vimentin, MMP-2, MMP-9, PI3K, Akt, p-Akt, mTOR, and p-mTOR was determined by Western blot, and the m RNA expression of PI3K, Akt and mTOR was determined by real-time polymerase chain reaction.RESULTS:BJ-EZ group inhibited proliferation after 24, 48, and 72 h compared with the NC group(P < 0.01 or < 0.001) and reduced the invasion and migration of MDA-MB-231 cells(P < 0.01 or < 0.05, P < 0.01 or P < 0.001), and inhibited the m RNA and protein expression of PI3K, Akt(p-Akt),mTOR(p-mTOR)(P < 0.05, < 0.01 or < 0.001).CONCLUSION:Biejia(Carapax Trionycis) and Ezhu(Rhizoma Curcumae Phaeocaulis) couplet medicine can inhibit the proliferation, invasion, migration and EMT of MDA-MB-231 cells through PI3K/Akt/mTOR signaling pathway, and the effect is better than that of Biejia(Carapax Trionycis) or Ezhu(Rhizoma Curcumae Phaeocaulis) alone.