A field experiment was conducted to study the effects of applying sodium selenate (0, 100, 200, 300 and 400 g/hm²) on the yield and nutritional quality of oil sunflower in order to provide scientific reference for the comprehensive utilization of local saline-alkali land and the production of selenium-rich agricultural products. The results showed that the yield of oil sunflower was increased by applying 300 g/hm² of sodium selenate, while decreased by applying 100-200 g/hm² or 400 g/hm² of sodium selenate; Applying 200-300 g/hm² of sodium selenate increased the contents of K, S, Fe, Zn, Mn, Cu, Se, oleic acid and linoleic acid, inhibited the absorption of Cr, Cd and Pb, and decreased the contents of palmitic and stearic acids in sunflower seed kernels. By considering both yield and its nutritional quality, applying 300 g/hm2 of sodium selenate is recommended as the effective way for oil sunflower in the saline-alkali soil.