Abstract: Objective: To construct expressing vector of short hairpin RNA (shRNA) targeting Bcl2, and investigate the effect of Bcl-2 shRNAs on the growth of acute promyelocytic leukemia cell line NB4. Methods: Recombinant expression vector expressing Bcl-2 shRNAs was identified by enzyme cutting and sequencing analysis. Bcl-2 shRNAs were transfected into NB4 cells with Lipofectamine. Transfected cells were visualised using inverted fluorescent microscope and then assayed by flow cytometry.The expression levels of Bcl-2 protein were assayed by Western-blot. Cytotoxic effects were measured by use of MTT method. Results: Enzyme cutting and sequencing showed that the insertion sequence was correct. Western-blot assay showed that the expression levels of Bcl-2 protein from NB4 cells decreased after Bcl-2 shRNAs treatment. There was no difference in Bcl-2 protein levels between control shRNA and untreated cells. The growth of NB4 cells was significantly inhibited at 72 and 96 h after treatment with Bcl-2 shRNA1 or Bcl-2 shRNA2 as compared with that after treatment with control shRNAs, vector and untreated NB4 cells, respectively (P<0.05). Conclusion: Bcl-2 shRNA expression vectors could effectively inhibit the growth of NB4 cells.