Abstract: ‘Naihanyouxiu’ broccoli variety used as the test material, different concentrations(0 mg·L^-1,2.5 mg·L^-1,5.0 mg·L^-1,10.0 mg·L^-1,25.0 mg·L^-1) of exogenous substance Na₂SeO₃ were used to treat broccoli.The effects of different concentrations of exogenous substance Na₂SeO₃ on the nutritional quality and glucosinolate content of broccoli were studied by determining the contents of vitamin C,soluble sugar, soluble protein, crude fiber, polyphenols, total flavonoids and glucosinolates, in order to provide technical reference for strengthening the nutrition and active ingredient of broccoli.The results showed that under the treatment of different concentration of Na₂SeO₃,there was no significant difference of soluble sugar in broccoli; when the concentration of Na₂SeO₃ was 5.0 mg·L^-1,the contents of vitamin C and soluble protein and dry crude fiber were the highest, which were increased by 5.31%,17.99% and 6.02%,compared with CK,respectively.When the concentration of Na₂SeO₃ was 10.0 mg·L^-1,the polyphenol content was the hightest, when the concentration was 5.0 mg·L^-1,it was the second content, there was no significant difference between them, which increased by 20.18% and 4.61%,compared with CK,respectively.When the concentration of Na₂SeO₃ was 5.0 mg·L^-1,the contents of aliphatic glucosinolates（not included ERU and 4 OH）,indole glucosinolates and total glucosinolates in broccoli were increased, and the content of these glucosinolates were the highest in all treatments.In conclusion, different concentrations of exogenous substance Na₂SeO₃ on the nutritional quality and glucosinolate content of broccoli produced a greater impact, which the concentration of 5.0 mg·L^-1 Na₂SeO₃ had the most efficient.