The effects of sodium selenite(Na2SeO3) on the morphology,growth and antioxidant capacity of channel catfish ovary cell(CCO) were investigated by inverted microscope and the method of MTT.The results showed the effects of Na2SeO3 on CCO were in dose response and related with time.Low doses of Na2SeO3 had little effect on CCO,while higher dose(≥5 μmol/L) significantly inhibited the cell viability and finally induced cell death.The longer the incubation time was,the stronger the damage was.Na2SeO3 at high concentration(≥10 μmol/L) induced CCO oxidative damage due to its oxidant properties.Significant decreases in activities of SOD and GSH-Px were observed.The level of lipid peroxidatioin(the content of MDA) and the release of LDH increased significantly.