To study the correlation of the reversal effect of tetrandrine (Tet) in combination with droloxifene (DRL) on multidrug resistant cell line K562/A02 and induction apoptosis, the apoptosis of K562 cells and K562/A02 cells after the treatment of Tet and DRL alone or their combination was detected by flow cytometry (FCM). The results showed 0.62 microg/ml Tet and 1.94 microg/ml DRL alone could induce apoptosis of K562 cells in time-dependent manner after culture for 48 hours. Neither Tet at 0.62 microg/ml nor DRL at 1.94 microg/ml alone could induce apoptosis of K562/A02 cells, but in the combination of them two induced apoptosis of few K562/A02 cells in culture for 72 hours. In conclusion, the mechanism of Tet and DRL reversing multidrug resistance has no correlation with the apoptosis of K562/A02 cells.