Swine umbilicus veins were isolated in sterile, 0.1% collagenase I was poured into umbilicus vein to digest, primary swine umbilical vein endothelial cells (SUVECs) were obtained and cultured in Dulbeccos modified Eagles medium (DMEM) supplemented with 20% fetal calf serum at 37℃ and 5% CO2.However, usually contain a number of contaminating non-endothelial cells.To over this major drawback, we use fluorescent activated cell sorting (FACS) techniques to purify swine umbilical vein vascular endothelial cells with CD31-FITC monoclonal antibody, which is special marker protein of endothelial cells.The cells formed a confluent monolayer, looked like cobblestones morphology which is confirmed as typical endothelial phenotype.The 7th generation of SUVECs were transfected with a mixture of pCI-neo-hTERT.plasmid and lipofectamine.Positive clones obtained by selecting with 500 μg/ml G418 and were expanded for further culture.The telomerase activity of the transfected cells were detected by TRAP-ELISA, the results showed the activity of telomerase was positive, while the activity of telomerase of SUVECs without transfection was negative.RT-PCR and Immunohistochemical staining assay showed positive expression for factor Ⅷ relative antigen(vWF) 、 CD34、 CD31 ,which are all the special markers of endothelial cells ,while α-SMA was negatively expressed.It shows that cells cultured are endothelial cells.SUVECs transfected with hTERT have the capacity to proliferate for more than 50 passages over 7 months and constantly express endothelial marker proteins, indicating that we have generated a stable endothelial cell line closely related to the corresponding primary cells ,we named it immortal SUVECs (iSUVEC).