The cell toxicity of different concentration of ginger oleoresin on mesenchymal stem cells (MSCs) was judged by MTT(Methyl thiazolyl tetrazolium). Flowing cytometry experiment was taken to observe the change of reactive oxygen species (ROS). Comet assay was used to detect the DNA damage. RT-PCR and Western Blot were used to detect the expression level of nuclear factor-E2-related factor 2 (Nrf2) protein and two typically recognized Nrf2 downstream genes, heme oxygenase-1 (HO-1) and NAD (P) H quinine oxidoreductase 1 (NQO1). The results showed that ginger oleoresin can reduce the level of ROS and the DNA damage of MSCs, induced by irradiation, and increase the expression of HO1 and NQO1 in mRNA and protein levels, which suggests that ginger oleoresin can reduce the oxidative damage of radiation, performing the role of radioprotective. Its mechanism may be related to Nrf2.Cited