Objective To explore raddeanin A(RA) inhibiting the proliferation of HCT116 cells and its related mechanism.Methods The MTT method was used to observe the RA inhibition on the proliferation of gastric cancer cells HCT116.Flow cytometry was used to detect the RA effects on cell apoptosis.Transmission electron microscope(TEM) was used to observe RA induced autophagy.Western blot was used to test expression of apoptosis and autophagy related proteins.Results RA could significantly inhibit the proliferation of HCT16 cells with concentration and time dependence;double layer membrane of autophagosome was detected by TEM;FCM showed that RA induced apoptosis in HCT116 cells,moreover the apoptosis rate was increased with the concentration increase;Western blot showed that the expression of autophagy related proteins(Beclin1 and LC3) was increased,the expression of apoptosis inhibition protein Bcl-2 was decreased.On the contrary,the expression of apoptosis promotion proteins(Bax,Cleaved-caspase-3,Cleaved-PARP) was increased,the expression of mTOR protein in the mTOR signal pathway was increased,while the p-mTOR protein expression was decreased.When the mTOR pathway inhibitor rapamycin(RAPA) was added to cells,Beclin-1,LC3,Cleaved-caspase-3,Cleaved-PARP proteins were increased,and apoptosis rate was also increased.Conclusion RA can inhibit the proliferation of HCT116 cells and can induce cellular autophagy and apoptosis,its mechanism may be realized by regulating the mTOR signal pathway.