In this paper,effects of exogenous selenium on the activity of superoxide dismutase(SOD),peroxidase(POD),glutathione peroxidase(GSHPx)and the content of soluble sugar and crude protein were studied by spraying selenium on the plants.The results showed that activities of SOD,POD and GSHPx were increased firstly and then decreased with the increasing of selenium concentration in the range of 0~45 g/hm2.And presented the best effect at 30 g/hm2 of selenium.Compared with the control,the content of soluble sugar and crude protein of millet grain was increased by 32.6% and 24.4% respectively when selenium concentration was 30 g/hm2 for Jigu 19,the content of soluble sugar was increased by 25.9% when selenium concentration was 15 g/hm2 and the content of crude protein of millet grain was increased by 187% when selenium concentration was 30 g/hm2 for Jigu 21.