目的　探讨骨髓间充质干细胞 (MSCs)的细胞生物学特性。　方法　免疫细胞化学检测细胞ALPase、Vimentin和Laminin活性。流式细胞术测定细胞周期和细胞表面抗原。MTT法测定细胞的生长曲线。原位杂交检测细胞端粒酶活性。　结果　MSCsALPase和Laminin呈阴性 ,Vimentin呈阳性。细胞周期中G1、S、G2期的细胞所占百分比分别为 89 5 %、7 8%、7 7% ;MSCs具有独特的表现特征 ,即CD16 6、CD2 9、CD4 4、CD10 5表达呈强阳性 ,阳性率高达 96 7%以上 ,而CD34和HLA DR呈阴性表达。细胞的平均倍增时间为 32h。细胞端粒酶活性呈阳性反应。　结论　培养的细胞为未分化的骨髓间充质干细胞 ,而不是造血干细胞和成纤维细胞 ,且细胞具有较强的增殖能力。 Objective To investigate the cell biology of bone marrow mesenchymal stem cells (MSCs). Methods Immunocytochemistry was used to detect the activity of ALPase, Vimentin and Laminin. Flow Cytometry to Determine Cell Cycle and Cell Surface Antigen. MTT assay of cell growth curve. In situ hybridization was used to detect telomerase activity. Results MSCs ALPase and Laminin were negative and Vimentin was positive. The percentage of cells in the G1, S, G2 phases of the cell cycle was 89.5%, 78%, 77% respectively. MSCs had unique characteristics, ie, the expression of CD16 6, CD2 9, CD4 4 and CD10 5 was strong Positive, the positive rate of 96 7% or more, and CD34 and HLA DR negative expression. The average cell doubling time was 32h. Cell telomerase activity was positive. Conclusion The cultured cells are undifferentiated bone marrow mesenchymal stem cells, rather than hematopoietic stem cells and fibroblasts, and the cells have strong proliferative capacity.