Abstract: Objective To investigate the effect of down-regulation of nuclear factor erythroid 2-related factor（Nrf2） by RNAi on biological behaviors in esophageal cancer cells. Methods Eca-109 cell line which was down-regulated Nrf2 by RNAi（Si-Nrf2） and negative control cell（Si-control） were established. Si-Nrf2 cells and Si-control cells were transfected by Lipofectamine 2000. Cell proliferation， apoptosis， cell metastasis and relative protein expression were analyzed by MTT assay， colony formation assay， flow cytometry， transwell and western blotting method after transfection. Results Western blotting showed that the expression of Nrf2 in the Si-Nrf2 cells was 0.209±0.013， which was significantly lower than that in the Sicontrol cells（0.852±0.077， P＜0.05）. The result of biological function shown that Eca-109 cell down-regulated Nrf2 had a lower survival fraction， higher cell apoptosis， and significant decrease in migration and invasion， higher radiosensitivity and lower expression of HO-1， Bcl-2， MMP-9 protein compared with those of Si-control cells（P＜0.05）. Conclusion Nrf2 may involve biological process of cell proliferation， apoptosis， invasion and metastasis and radiation sensitivity in esophageal cancer by regulating the expression of HO-1， Bcl-2 and MMP-9 protein.