Objective:To investigate the protein expression of GTPBP4 in human hepatocelluar carcinoma (HCC) tissues and the influ-ence of GTPBP4 silencing by siRNA on the proliferation and cell cycle of HCC cell line Hep G2. Methods:Western blot analysis was per-formed to observe the protein expression of GTPBP4 in 24 cases of HCC tissues compared with their adjacent noncancerous liver tis-sues. Lentivirus-mediated RNA interference (RNAi) was used to silence GTPBP4 expression in Hep G2, and the infection efficiency was observed under a fluorescence microscope. The silencing effect was tested by Western blot and real-time PCR. After silencing the GT-PBP4 gene, cell proliferation was detected using CCK-8 assay, and the cell cycle was observed using flow cytometry. Results:(1) GT-PBP4 was overexpressed in 21 cases (87.5%) of HCC tissues (P<0.000 1). (2) After the lentivirus with GFP reporter infected the Hep G2 cells, 90%of the cells showed green fluorescence. LV-GTPBP4-RNAi effectively inhibited the expression of GTPBP4 at both mRNA (70%) and protein (67%) levels. (3) The proliferation ability of the LV-GTPBP4-RNAi group significantly decreased after 96 h (inhibition rate:54.51%). Flow cytometry showed that the LV-GTPBP4-RNAi group significantly increased at the G0/G1 phase, whereas the S phase de-creased and arrested at the G0/G1 phase. Conclusion:GTPBP4 overexpression in HCC tissues was associated with hepatocarcinogenesis and promoted tumor cell proliferation, but the specific molecular mechanisms remain to be investigated.