Senescence marker protein 30 (SMP30), a hepatocellular carcinoma (HCC) associated antigen had beenidentified by our research group. To study its mechanisms of regulation and associations with the occurrenceand development of HCC, we inhibited expression by RNAi technique, and observed effects on the biologicalcharacteristics of Hep G2 cells. In cell viability assays, cell growth in the experimental group (with siRNAtransfection) was elevated. In Transwell invasion assays, compared with blank and control groups, numbers ofinvading cells in the experimental group were significantly increased, whereas in apoptosis assays, the percentageapoptosis demonstrated no differences, but after UV irradiation, that in the experimental group was higher thanthe other two groups. In a word, SMP30 can inhibit the proliferation and invasion of human hepatoma cells andthus can be regarded as a cancer suppressive factor.