The aim of study was to investigate the inhibitory effect of small interfering RNA on evi1 gene expression and biological characteristics in HEL cells and its mechanism. 3 siRNA (siRNA-1, siRNA-2, siRNA-3) specific for evi1 gene were synthesized and transfected into HEL cells in vitro. Experiments were divided into test and control groups. MTT method was used to assay the inhibitory effect of siRNA on cell proliferation; semiquantitative RT-PCR was used to detect the expression of evi1 gene mRNA; the cell viability was determined by trypan blue dye test; the change of cell cycle and apoptosis of cells were analyzed by flow cytometry. The results showed that siRNA-1 had strongest effect, and inhibitory effect was most obvious at 48 hours after transfection. When the concentration of siRNA raised to 120 nmol/L, the inhibitory rate reached to the peak. The inhibitory rate of siRNA-1 on proliferation of HEL cells, relative expression level of evi1 mRNA and cell viability at 48 hours after transfection were 72.22 ± 2.80%, 27.31 ± 1.11% and 26.05 ± 2.49%, which had significant difference from other groups (p < 0.001). The siRNA resulted in arrest of cell cycle at G(0)/G(1) phase, the cell amount at S phase obviously decreased, the apoptotic rate of HEL cells obviously increased (p < 0.01). It is concluded that the siRNA specific for evi1 gene can suppress the proliferation of HEL cells, reduce the expression of evi1 mRNA, decrease the cell viability, arrest the cell cycle at G(0)/G(1) phase, suppress cell mitosis, and promote cell apoptosis.