This study was aimed to investigate the biological characteristics of osteoblasts from patients with myelodysplastic syndrome (MDS) and their supportive capacity for hematopoiesis in vitro. A two-dimensional culture system was constructed by using osteoblasts derived from human marrow mesenchymal stem cells (MSC); MSCs were isolated from bone marrow of MDS patients and normal individuals and were cultured; the third passage of MSCs were induced into osteoblasts which were treated with mitomycin C and confluenced into a feeder layer. Ficolled bone marrow mononuclear cells were obtained from normal individuals and seeded into the two-dimensional culture system to culture in vitro without exogenous cytokines. By using colony-forming assay, the ability of the two-dimensional system to culture HPCs was observed. The cytokine expression of osteoblasts from MDS patient bone marrows in mRNA level was detected by RT-PCR and was compared with human osteoblast cell line hFOB1.19. The results showed that the osteoblasts from MDS patients could support short-term survival of GM-CFC in condition without exogenous cytokines, that is, osteoblasts played a crucial role in regulation of HPC growth. The results of RT-PCR clearly demonstrated that the osteoblast cell line hFOB1.19 expressed SCF, IL-6, SDF-1alpha, G-CSF and GM-CSF. The same expression patterns of above cytokines were also seen in osteoblasts derived from BM-MSCs of MDS patients and normal individuals, but these cells did not express GM-CSF. It is concluded that the biological characteristics of osteoblasts from bone marrow of MDS patients are generally not different from those of osteoblasts from normal bone marrow. Both of them can support GM -CFC to form colonies in vitro, it may be associated with expressing important related cytokines by osteoblasts.