Objective:To investigate the inhibitory effect of small interfering RNA(siRNA)on yes-associated protein(YAP) expression and adriamycin(ADM)chemosensitivity of hepatoma cell lines.Methods:The siRNA sequences were designed based on YAP gene and were transfected into four different kinds of hepatoma cells (PLC/PRF/5,Huh-7,MHCC 97H,MHCC 97L) through lipofectamineTM 2000.The inhibition result of YAP expression in hepatoma cells was measured by Western blotting and fluorescence microscope.The viability rate of hepatoma cells was measured by methyl thiazolyl tetrazolium(MTT)colori-metry after treating with different concentrations of ADM.Results:The siRNA expression vector to aim directly at YAP gene was constructed successfully.Western blotting revealed that transfection with siRNA could inhibit the expression of YAP pro-tein in hepatoma cell lines.The expression of YAP protein in hepatoma cell lines was specially and effectually inhibited by RNA interference(RNAi).MTT colorimetry detection result revealed that the viability rate of hepatoma cell lines significantly de-creased after transfection with YAP siRNA.Conclusions:Inhibiting the expression of YAP by siRNA can enhance the sensitivi-ty of hepatoma cell lines to ADM.