Abstract: Objective To detect the levels of serum hepatitis B virus(HBV) DNA of the patients with HBV-related hepatocellular carcinoma(HCC),explore the correlation between the low level replication of hepatitis B virus DNA and the pathogenesis of hepatocellular carcinoma,and investigate the clinical significance of detecting serum HBV DNA level in patients with chronic hepatitis B at a lower level of replication. Methods We selected 85 patients with continuous lower level of serum HBV DNA(＜1 000 IU/ml) among the patients with HBV-related HCC.The occurrence,development and evolution of their diseases were systematically reviewed.The serum samples of them were prepared for the tests of HBV markers,liver function,AFP and HBV DNA levels.The relations between the DNA level and other indexes were analyzed. Results Among the 85 HCC patients,15 cases(17.65%) were with HBeAg-positive,70 cases(82.35%) were with HBeAg-negative.52 cases(61.18%) were with abnormal(ALT and AST),65 cases(76.47%) were with an abnormal increase of AFP.72 cases(84.71%) were with low HBV DNA levels was more than 20 IU/ml,while 13 cases(15.29%) low HBV DNA levels less than 20 IU/ml. Conclusion HBV-related HCC is associated with the duration of hepatitis B virus replication.The conventional methods can only detect the HBV DNA levels more than 1 000 IU/ml.The patients with a low HBV DNA level are easy to be ignored,and receive timely the antiviral therapy that lead to disease development.The more precise detection methods for low HBV DNA level will have much clinical significance.