Objective: To investigate the effect of transforming growth fact or β1 gene transfer on the oncogene expression. Methods: Positi ve and reverse pL(TGFβ1 )SN were used to transfect PA317 and Ψ2 packaging cel l line by lipofectamine. After G418 selection, the positive cloning and serum of retroviral were obtained. Meanwhile, retroviral serum and positive, reverse TGF β1 gene were used for transfecting hepatocellular carcinoma cell line. Pos itive cell slide for immunohistochemical staining was prepared to observe change s in oncogene expression. Results: PL(TGFβ1 )SN was digested b y restriction enzyme. Positive and reverse fragments were formed. 290 bp Neo gene band was discovered by nested primer RT-PCR in all the samples. Conc lusion: Positive TGFβ1 gene reduces the c-myc, c-met and ras gene exp ression suggesting that TGFβ1 could act as a negative growth regulator for hu man hepatocellular carcinoma cells in vitro.