Hepatitis B virus (HBV) infection is endemic in Asia and causes major public health problems worldwide. Present treatment strategies for HBV infections are not satisfactory and the clinical limitation of current antiviral drugs for HBV, such as lamivudine, is causing rapid emergence of drug-resistant viral strains during the prolonged therapeutic treatment. In this research, the efficacy of a natural green tea extract (GTE) against HBV in a stably expressed HBV cell line HepG2-N10 is examined. The expression of viral antigens, HBsAg and HBeAg, were determined by using enzyme linked immuno-absorbent assay (ELISA). Quantitative real-time-PCR (Q-PCR) was used for the determination of extracellular HBV DNA and intracellular replicative intermediates and nuclear covalent closed circular DNA (cccDNA). HBV mRNAs were also analyzed by reverse transcription PCR (RT-PCR). Results showed that the 50% effective concentration (EC50) of GTE on HBsAg, HBeAg, extracellular HBV DNA and intracellular HBV DNA were 5.02, 5.681, 19.81, and 10.76 microg/ml, respectively. While the concentration of GTE with the inhibition percentage of 50% on proliferating cells (CC50) was 171.8 microg/ml. Similar analysis of the principal component of GTE, epigallocatechin gallate (EGCG), revealed it has relative weaker efficacy compared to GTE.