Aim To study on biological properties and hemopoiesis-supporting function of human bone marrow stromal cells cultured for long-term in vitro. Methods ① Bone marrow stromal cells from fetus, chidren and adults were cultured for long-time in vitro by static adherent wall assay. ② The phenotypes of the stromal cells were analyzed by immunocytochemical staining or FACA.③ Hemopoietic stem cells in umbilical cord blood were co-cultured and expanded with the stromal cells at different development stages. Results ① The fibroblast myoid cell lines were established and could be propagated to 10 generations and kept for 6 months, meantime, endothelial cells and macrophoges were obtained. ② The child stromal myoid cells were positive for viementin and negative for VIII factor by immunocytochemical staining and their phenotypes were CD33-,CD34-,CD38-and CDW90＋ , while the phenotypes of adult stromal cells were CD33-, CD34-, CD38＋ and CDW90＋ . ③ The stromal cellls could support long-time survival or expansion of LTC-ICs. Survival time of LTC-ICs in the stromal cell-supporting system supplemented with SCF, IL-3 and IL-6 was even longer than that in system without stromal cells(P∨ 0.01). The productivity rate of LTC-ICs cultured in the stromal cell-supporting system was 2 to 4 times higher than that cultured in system without stromal cells. Conclusion The human bone marrow stromal cells could be cultured for long-time in vitro and have hemopoiesis-supp ortingfunction for the hemopoietic stem cells in cord blood.