Objective：In this study，TNF-α treated mouse preosteoblast cell line MC3T3-E1 was used to investigate the effect of TNF- treated mouse preosteoblast cell line MC3T3-E1 on its hematopoiesis and its possible mechanism（s）. Methods：MC3T3-E1 cells pretreated with TNF-α were used as feeder layer cells，combined with hematopoietic growth factor SCF，TPO and Flt3-ligand，and Sca-1（+）cells of mice were amplified and sorted in vitro for 7 days，and the granulocyte - single-line colony formation unit（CFU-GM），red line formation unit（BFU-E）and pre-b line formation unit（CFU-pre-B）were detected. The effect of Erk inhibitor FR180204 on the levels of N-cadherin and p-Erk in MC3T3-E1 cells was also examined. Results：After pretreatment with TNF-α，the expression of N-cadherin was up-regulated，p-Erk was down-regulated，and p-Akt had no effect. The feeding layer cells combined with hematopoietic growth factor were amplified into Sca-1（+）cells in vitro for 7 days，compared with the control group，the number of total CFU，BFU-E and CFU-GM in TNF-α pretreatment group decreased（P < 0.05），but the number of CFU-pre-B increased significantly（P < 0.05）. Erk inhibitor FR180204 treated MC3T3-E1 cells，it showed down-regulated Erk and up-regulated N-cadherin levels. Conclusion：TNF-α may indirectly affect production of the blood and differentiation of hematopoietic stem cells into various lines by affecting hematopoietic supporting cells in bone marrow microenvironment. Regulation of the phosphorylation of Erk1/2 and the expression of N-cadherin in osteoblasts may be one of the mechanisms by which TNF-α affects bone marrow hematopoiesis