Abstract: The eukaryotic expression plasmid pCIneohTERT was transfected into goat endometrium stromal cells (ESCs). Then, the stable cell clones were selected, the cell phenotype, proliferation and growth characteristic were measured and also the effect of different level of sex steroids on the proliferation and differentiation of transfected ESCs were determined. The results showed that 5 cell clones were obtained. Antidrug cell clones were formed by screening with G418 after 23 weeks, and then using filter paper to expanded culture. Transfected cells showed the long spindleshaped or the triangle and arrange parallel after expanding cultured. Immunocytochemical staining method showed that the two shapes of stromal cells were positive for vimentin and negative for cytokeratin. It was morphologically and phenotypically similar to the primary goat ESCs. The number of cell passage increased after transfection and telomerase activity was positive at 45th passage. One of the clones was cultured up to 50 passages and steadily cultured. The combination of 100 nmol·L-1 E2 and 10 nmol·L-1 P4 in media could stimulate the proliferation of transfected stromal cells. In summary, the immortalized goat ESCs were got to facilitate the further studies of endometrium in vitro.