This study was purposed to investigate the apoptosis-inducing effect of astragalosides on acute promyelocytic leukemia(APL) cell line NB4 and its mechanism. NB4 cells were treated with different concentrations (200, 300, 400 µg /ml) of astragalosides for 48 h. The cell proliferation was assayed by using CCK-8 method; the cell apoptosis was analyzed by flow cytometry with Annexin V-FITE/PI double staining. The mRNA expression of BCL-2 and the relative activity of BCL-2, NF-κB and caspase-3 were detected by RT-PCR and Western blot, respectively. The results showed that after treated with astragalosides for 48 h, astragalosides inhibited NB4 cell proliferation in concentration-dependent way, the apoptosis rate of NB4 cells gradually elevated from 4.69% to 40.85% with the increasing of astragalosides concentration. Simultaneously, the mRNA expression of BCL-2 was down-regulated, Western blot analysis showed that the protein expression levels of BCL-2 and NF-κB decreased after astragalosides treatment, while caspase-3 protein expression level increased. It is concluded that the molecular mechanism of the astragalosides-induced apoptosis in NB4 cells may be associated with down-regulation of the expression of BCL-2 and NF-κB, finally the relative activity of caspase-3 activated.