Abstract: Objective：To investigate the effect of breast cancer cell growth, we utilized RNAi tragedy to inhibit hTERT gene in MCF-7 cells of breast cancer. Methods：Small intererence RNA (siRNA) homologous to hTERT gene (hTERT-siRNA) was recombined with pGenesil-1 vector, then transfected into MCF-7 cells of breast cancer to induce RNAi,and then hTERT gene expression alterations and tumor cell proliferation in both hTERT-siRNA treatment groups and control groups were detected by MTT assay, RT-PCR and Western blot. Results：The expression of hTERT had been obviously inhibited by siRNA.The inhibition rate of cell proliferation was 61.94%.The mRNA level of hTERT was obviously decreased by 61.7%, and its protein expression reduced by 52.8%. Conclusion：siRNA-hTERT effectively inhibited hTERT gene expression and breast cancer cell proliferation in vitro.