In order to achieve high-efficiency expression of exogenous protein in sheep lung fibroblasts OAR-L1, and to explore a suitable transfection method for the cell line, the transfection efficiencies of polyethyleneimine (PEI), Lipofectamine^TM 2000 transfection reagent (Lipo 2000), Cytofect^TM fibroblast transfection kit (CF2) and lentivirus mediated cell transfection in the OAR-L1 cells were compared. The results showed that when OAR-L1 cells were transfected with fluorescent plasmids pLentiCMV-EGFP-Puro or pLentiCMV-mCherry-Puro, PEI-, Lipo 2000- and CF2-mediated transfection could be affected by the cell density and the amount of transfection reagents, besides the best transfection efficiency of each method was less than 30%. While the number of fluorescent cells obtained by lentivirus-mediated cell infection was not limited by these two factors, and was significantly higher than the former three methods. The recombinant virus solution could be stored at 4 or －80 ℃ for at least 15 d without decline of the infection efficiency. To co-express two exogenous proteins in the OAR-L1 cells, mixing two packaged lentivirus in equal proportions followed by infection could achieve a higher co-transformation rate. The above results show that lentivirus infection is a cell transfection method that could achieve high expression of exogenous proteins in the OAR-L1 cells, and provide certain references for the selection of transfection methods for other difficult-to-transfect cells.