Objective To investigate the expression changes of nuclear factor kappa B (NF-κB) and matrix metalloproteinase-9 (MMP-9) in the cultured hepatocellular carcinoma cells 9204 (HCC9204) transfected with inhibitory kappa B alpha（IκB-α)vector. Methods After pcDNA3-IκB-α vector and pcDNA3 were transfected into HCC9204 by lipofectamine method, Western-blot and RT-PCR analysis were used to detect the expressions of NF-κB and MMP-9. Migration and invasion of tumor cells were assayed by fundus membrane invaded by them. Results When pcDNA3-IκB-α was transfected into HCC9204, the expression of NF-κB was decreased at the protein level, and the expression of MMP-9 mRNA and the invision and metastasis ability of transfected cells were obviously decreased. Conclusion When the activity of NF-κB is inhibited, the ability of invasion and metastasis in HCC9204 cells decrease, which could be related to the decreased the expression of MMP-9.