HBV infection remains a major health problem in the world. Several data have revealed that lamivudine can efficiently promote the treatment of hepatitis B. However, a long-term treatment of lamivudine leads to the emergence of lamivudine-resistant mutants (YMDD mutants), which hampers the anti-HBV therapy. Therefore, researches related to HBV lamivudine-resistant mechanism has been of great significance. Up to date, many researches using eukaryotic plasmids containing either one type of HBV YMDD mutant or wild-type strains, without specification of HBV genotype, were reported.