Objective:This study aimed to explore the distribution and speciation of selenium amino acids in different solubilized proteins of selenium-enriched broccoli, soybean, corn and barley seedlings.Methods:The contents of selenomethionine, selenocysteine, methylselenocysteine and selenethionine in four selenium-enriched cereals and cruciferous agricultural products were determined by high performance liquid chromatography-hydride generation-atomic fluorescence spectrometry. Moreover, the distribution characteristics of each selenium amino acid in albumin, globulin, gliadin and glutelin with different solubilized proteins were analyzed.Results:The content and distribution of selenium amino acids of the four selenium-enriched plants in different protein components were significantly different (P＜0.05). SeMet was the main organic selenium form in selenium-enriched soybean, corn and barley seedlings, and its distribution of the four types of protein fractions was more consistent and the relative contents were all higher than 66%.However, no SeEt was detected. The organic selenium forms in selenium-enriched broccoli were mainly SeCys2 and SeMet, following by MeSeCys. SeCys2 and SeMet were more uniformly distributed in the albumin and glutenin which accounted for about 36% of the organic selenium content, but SeMet was present in the globulin and gliadin with the highest relative content of 60%. SeCys2 accounted for about 34% of the organic selenium content, while SeEt was the smallest constituent accounted for about 5%.Conclusion: SeMet is the main selenium specie in different soluble proteins of Graminaceous and cereals (selenium-enriched soybean, corn and barley seedlings); SeMet and SeCys2 are the main selenium species in different soluble proteins of selenium-enriched broccoli, and there are also MeSeCys in albumin and glutelin.