The objective of this study is to observe the effects of siRNAs which are synthesized from human inhibitor of apoptosis protein 2 (hIAP-2) on the proliferation and apoptosis of HepG2 cells. HepG2 cells were transfected through liposome mediated transfection method with 3 strands of hIAP-2-siRNA synthesized through chem. method, and the normal liposome were used as the control. The hIAP-2 mRNA and protein expression were tested using RT-PCR and Western blotting after hIAP-2-siRNAs taking effects. The cell proliferation and apoptosis were detected by MTT and AV-PI flow cytometry, resp. The results showed that the of RT-PCR and Western blotting showed that all of 3 pieces of siRNA can inhibit hIAP-2 mRNA and protein expression effectively (P<0.05), especially siRNA 1 (P<0.05). MTT showed that the proliferation of HepG2 cells that were transfected by hIAP-2-siRNA of 80 nmoL·L-1 has been remarkably inhibited (P<0.01), and cell proliferation declined greatly after 72h of transfection by hIAP-2-siRNA of 80 nmoL·L-1 (P<0.01). The result of flow cytometry showed that the apoptosis rate of HepG2 cells transfected by hIAP-2-siRNA raised (P<0.05). It was concluded that the hIAP-2-siRNA can inhibit the proliferation of this tumor cells, and promote HepG2 liver cancer cells apoptosis.