This study was purposed to investigate the effect of small interfering RNA against c-myc on c-myc, h-tert gene and protein expressions in acute lymphoblastic leukemia cell line (Jurkat cells), so as to provide new methods and targets for gene therapy of leukemia. The siRNA against target sites 1545-1565 of c-myc mRNA was chemically synthesized and was transfected into Jurkat cells by transfectant. The c-myc, h-tert mRNA and protein expression levels before and after treatment with c-myc siRNA were detected by RT-PCR and Western blot, respectively. The results showed that c-myc siRNA obviously inhibited the proliferation of Jurkat cells, the half inhibitory concentration (IC50) for 48 hours was about 75 nmol/L. c-myc siRNA could decrease c-myc, h-tert mRNA and C-MYC, h-TERT protein expression levels of Jurkat cells. It is concluded that c-myc siRNA significantly reduce c-myc, h-tert mRNA and protein expression levels through inhibiting c-myc mRNA expression and decreasing intracellular level of C-MYC protein.