Objective  To investigate the effect of tumor necrosis factor-α(TNF-α) on biological properties of dental pulp stem cells (DPSCs) in low-oxidation stress.    Methods  The experimental groups were as follows: normox, normox control plasmid, normox-TNF-α, 3% O2, control plasmid-3% O2、TNF-α-3% O2.DPSCs were resuscitated and cultured firstly, then lentivirus TNF-α transfected cells were cultured in a CO2 incubator at 37 ℃. The expression of TNF-α  was detected by ELISA in each group, and the expression of TNF-α under oxidative stress was detected by RT-PCR,the expressions of alkaline phosphatase(ALP) and dentin sialophosphoprotein(DSPP) were detected by Real-time PCR and Western blotting,the proliferation of DPSCs cells transfected with TNF-α was detected by flow cytometry and MTT.    Results  After lentivirus-TNF-α transfected cells for 10 hours, the green fluorescence signal could be observed under inverted fluorescence microscope, TNF-α overexpression could enhance the proliferation of DSPP in hypoxic environment,and hypoxia microenvironment can greatly increase the expression of TNF-α, Western blotting and Real-time PCR showed that there were significant differences in the expression of ALP and DSPP in DPSCs（P<0.05）.    Conclusion  TNF-α overexpression can improve the proliferation efficiency and differentiation efficiency of DPSCs in hypoxic microenvironment.