Abstract: Objective　To establish hepatitis B virus（HBV）X gene eukaryotic expression vector and identify its expression. Methods　Polymerase chain reaction（PCR）was used to amplify X gene sequence，and the pcDNA6（＋）vector and X gene PCR product double enzyme digestion transformed into Escherichia coli DH5 alpha.The positive clones were screened，and the double enzyme digestion and DNA sequencing were used to establish HBV X gene eukaryotic expression vector pcDNA6（＋）-HBx.By polyetherimide（PEI）method，the transformation into HepG2 cells was performed，and Western blot identification of target protein was carried out. Results　After pcDNA6-HBx enzyme digestion，agarose gel electrophoresis found HBx gene fragment，and sequencing results showed containing the complete X gene fragment.Western blot results showed that the pcDNA6（＋）-HBx in HepG2 cells expressed X protein. Conclusions　The eukaryotic expression vector pcDNA6（＋）-HBx is established successfully，and there is X protein expression in HepG2 cells. It provides convenience for the further study of HBV X gene with chronic hepatitis and hepatocellular carcinoma.

Key words: Hepatitis B virus, X gene, Eukaryotic expression