Abstract: Objective To construct a lentiviral vector encoding human estrogen related receptor alpha (hERRα) gene and to study the influence of lenti-ERRα on A549 cell prolifertation.Methods A fragment of the hERRα gene was amplified with PCR and was inserted into the plasmid pWPXLD.The three plasmids(pWPXLD-hERRα,psPAX2,and pMD2G) were cotransfected the virus packaging cell line 293T using the Ca₃(PO₄)₂ method.Then the cell supernatant was harvested and the virus titration was determined after concentration.Also the expression of hERRα in human lung cancer cell line A549 cells infected by the lentivirus was determined with western blot.The effect of ERRa overexpression on the A549 cell grow th was detected by Cell Titer Glo kit.Results DNA sequencing demonstrated that the recombinant plasmid pWPXLD-Herr was successfully constructed.The titration of the concentrated lentivirus was 1.8×10⁸ TU/mL.Western blot assay proved positive for the hERRα.Cell-Titer Glo results revealed that overexpression of hERRα in A549 cells up-regulated the cell viability.Conclusion Lentivirus encoding hERRα was successfully constructed and hERRα could express in A549 cells.The overexpression of hERRα in A549 cells up-regulates the cell viability.