Purpose: To investigate the effect of survivin-short hairpin RNA (shRNA) on the proliferation, apoptosis and radiosensitivity of human hepatoma SMMC-7721 cells.Materials and Methods: Survivin-targeted small interfering RNA (siRNA) expression vector was constructed and transfected into SMMC-7721 cells mediated by cationic liposome.Survivin mRNA and protein expression were analyzed by Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and Western blotting.Cell viability was measured by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay.Cell cycle and apoptosis were measured by flow cytometry (FCM) assay.Radiosensitivity of SMMC-7721 cells was examined using a colony-forming assay.Mice subcutaneously implanted with SMMC-7721 cells were monitored for tumor growth and survival after treatment, and tumors were analyzed for proliferation, apoptosis, and angiogenesis biomarkers by immunohistochemistry staining.Results: After transfection, the mRNA and protein expression of survivin gene in SMMC-7721 cells downregulated, which led to significant cell growth inhibition, cell arrest in G2/M phase, increased apoptotic rate and radiosensitivity.Survivin-shRNA in combination with radiotherapy is more effective than radiotherapy or survivin-shRNA therapy alone in suppressing tumor growth and extending survival duration.Combined therapy inhibited cell proliferation and tumor angiogenesis and increased apoptosis in tumor xenografts.Conclusions: Survivin downregulation by siRNA/cationic liposome inhibited proliferation, induced apoptosis and enhanced radiosensitivity in human hepatoma cells in vitro and in vivo.