目的　探讨Ｆｌｔ３ 配基（ＦＬ） 、Ｔｐｏ、ＳＣＦ等细胞因子组合对人脐血干／ 祖细胞的扩增及自我更新能力的维持作用。方法　用ＦＬ＋ Ｔｐｏ＋ ＳＣＦ＋ＩＬ６ ＋ＩＬ３＋ ＧＣＳＦ组合，体外扩增脐血ＣＤ３４ ＋ 细胞１４天，将其移植给亚致死剂量照射的ＳＣＩＤ小鼠。结果　扩增的脐血造血细胞可顺利植入ＳＣＩＤ小鼠并重建造血，１８ 只小鼠移植后存活６ 周的有８ 只，其骨髓中仍可检测到人的造血细胞，死亡率５６ ％ ，与对照组（ 死亡率１００％） 比较，χ２ ＝１０．０８，Ｐ＜０．０１。结论　ＦＬ＋ Ｔｐｏ＋ ＳＣＦ＋ＩＬ６ ＋ＩＬ３ ＋ ＧＣＳＦ组合在有效扩增造血细胞的同时可保留造血干／祖细胞的自我更新及造血重建能力。 Objective To investigate the maintenance effect of Flt3 ligand (FL), Tpo, SCF and other cytokines on the expansion and self-renewal ability of human umbilical cord blood stem / progenitor cells. Methods The cord blood CD34 + cells were expanded in vitro using FL + Tpo + SCF + IL6 + IL3 + GCSF combination for 14 days and then transplanted into SCID mice sub-lethally irradiated. Results The expanded cord blood hematopoietic cells could be successfully implanted into SCID mice and reconstitute the hematopoiesis. Eight of the 18 mice survived 6 weeks after transplantation and the human hematopoietic cells were still detected in the bone marrow with a mortality rate of 56% Compared with the control group (mortality 100%), χ2 = 10.08, P <0.01. Conclusion The combination of FL + Tpo + SCF + IL6 + IL3 + GCSF can effectively retain hematopoietic stem / progenitor cells and enhance the capacity of hematopoietic reconstitution while effectively expanding hematopoietic cells.