Abstract: Effect of selenium supplementation on growth performance and immune function of oxidative stressed piglets were studied in this experiment.Fortyeight weanling piglets without vaccination for swine fever were allotted into four groups according to a one factorial design.Each group had six replications with two piglets each.Piglets received injection of diquat at the beginning of the trial.Selenium was supplemented at 0,0.2,0.4 or 0.6 mg/kg in the diets.At the end of the third week of the trail,all the pigs were injected with swine fever vaccine.The results showed that selenium supplementation could alleviate the impacts of oxidative stress.The growth performance and immune function of oxidative stressed piglets were significantly improved as selenium level in the diet increased,compared with other groups,the effect of 0.6 mg/kg group was the best.