Abstract: Objective: To study the association of hepatitis B virus (HBV)X gene and its mutation with hepatocellular carcinogenesis (HCC).Methods: HBV X gene in the liver tissues of 22 HCC patients whose hepatitis B surface antigen (HBsAg)was positive and 15 chronic asymptomatic carriers (CAC)patients were detected wih polymerase chain reaction (PCR);the PCR product was sequenced and analyzed;5 normal liver tissues with negative HBsAg acted as control.Results: The detection rate of HBV X gene in the carcinoma tissues of 22 HCC patients and 15 CAC patients was 68.18% and 46.67%,respectively.HBV X gene was not detected in the 5 normal liver tissues.The difference was significant between them (P<0.05).The detection rate of HBV X gene in carcinoma tissues and CAC liver tissues had no statistical difference (P>0.05).The double mutation rate of 1 762T/1 764A in carcinoma tissues and CAC liver tissues was 93.33% and 2/7,respectively.And the former was higher than the latter (P=0.004 3).There was no detection of mutation of 1 762T or 1 764A alone.Conclusions: There is a high detection rate of HBV X gene and a high double mutation rate of 1762T/1764A in the carcinoma tissues of HCC patients.HBV X gene and double mutations may play an important role in the carcinogenesis of HCC.