Abstract: Objective To study the effect of RNA interference on leukemia cell line U937 proliferation and apoptosis by inhibiting HOXA7 expression, to look for a new potential target for gene therapy for leukemia. Methods The experiment was divided into three groups: the experimental group, the blank control group and the negative control group. We created the specifi city eukaryotic expression vector of targeting HOXA7 and the negative control vector fi rst, then transfect them into U937 cells. The mRNA and protein expression of HOXA7 were determined by RT-PCR and Western blot . The proliferation of U937 in every group after 24, 48 and 72 h were detected by MTT. The apoptosis of U937 in every group after 48h was detected by flow cytometry. Results The HOXA7 expression was inhibited effectively, with the inhibition rates (47.314±7.394)% and (52.371±9.258)% on mRNA and protein levels in the experimental group,repectively. The MTT results showed the proliferation inhibition rate of 24, 48, 72 h were (15.062±5.086)%, (30.052±4.016)%, (52.617±9.292)% in the experimental group, respectively. Compared with the experimental group, prolferation inhibition rates of other two groups showed significant difference at the same time(P<0.05). Moreover, the inhibition effect of proliferation increased with extended time. The fl ow cytometry results showed the apoptosis rate of the experimental group was (24.677+4.161) %. And the differences of inhibitory rate and apoptosis rate in the experimental group were statistically signifi cant compared with blank control group and negative control group(P<0.05). Conclusion The eukaryotic expression vector targeting HOXA7 could inhibit proliferation and promote apoptosis of U937 cells effectively after HOXA7 expression suppression. HOXA7 was expected to become the new target of leukemia gene therapy.