Abstract: Objective To investigate the effects of down-regulating B-cell chronic lymphocytic leukemia /lymphoma 11B gene expression on the proliferation and apoptosis of Molt-4 cells. Methods The small interfering RNAs targeted on bcl11b gene were transfected into Molt-4 cells by nucleofector techique. The levels of bcl11b mRNA expression were analyzed at different time points after nucleofection by Real-time quantitative PCR. The cells proliferation rate was evaluated by MTT assay.Cell aapoptosis was detected by flow cytometry and modified Wright staining. Results The survival rates of siRNA-transfected cells had significantly decreased since the 24 hours after transfection (P<0.01). Apoptosis of treated molt-4 cells could be identified. The level of bcl11b mRNA expression was decreased. Conclusion bcl11b gene expression was inhibited by RNA interference selectively.Itmight inhibit the proliferation and induced the apoptosis of leukemia T cells.