Aim: To investigate the effect of osteopontin (OPN) expressions down-regulated by RNA interference (RNAi) on the invasion and metastasis of human hepatocelluar carcinoma (HCC). Methods: HCC cell line (HCC-LM3) was transfected with the chemically synthesized small interfering RNA (siRNA) in study arm and with non-specific siRNA in control arm. Real-time PCR and Western blotting were used to quantify the mRNA and OPN protein levels. The malignant phenotypes including cellular growth rates, colony formation and Matrigel invasion activities of the HCC cell line were analyzed. Results: In study arm OPN mRNA expressions decreased 75% and OPN protein decreased 80% compared to those of blank arm. The number of formed colonies and migrating numbers of the cells in vitro decreased significantly (64.6% and 59.6% respectively) in study arm compared to these of blank controls (p<0.05). The parameters in the control arm did not differ from those of the blank arm (p>0.05). Conclusion: The specific siRNA was able to reduce OPN expressions at both the mRNA and protein levels and significantly diminished the invasiveness of HCC cells. Methods: The expressions of MIF and VEGF in HCC and adjacent tissues were detected from 4 patients. Specific siRNA targeting MIF gene was synthesized, and transfected into the HCC cell lines (PLC and HepG2) in study group and non-specific siRNA was used in controls. The mRNA and protein expressions of MIF and VEGF were examined by PCR and western blot. Results: MIF and VEGF mRNAs were overexpressed in the HCC tissues compared with adjacent tissues (RQ=8.91±1.85 and 3.00±0.86, P 0.01). The mRNA and protein expressions of MIF and VEGF of HCC cell lines significantly decreased in study group compared with controls (P 0.01). VEGF mRNA levels decreased 75.6%±2.6%; 79.8%±1.2% in PLC, and 73.6%±4.6%; 80.7%±2.2% in HepG2 cells when disposed with siRNA 50nM and 100nM. VEGF protein levels also significantly reduced in study group P 0.01 . Conclusions MIF and VEGF mRNAs were overexpressed in the HCC tissues in vivo, and MIF siRNA was able to knock down the expressions of MIF and VEGF in HCC cell lines in vitro.