In order to evaluate the effects of bio-fortification on producing Se-enriched agricultural products, the content, speciation and bioaccessibility of selenium in Se-enriched plant materials supplied by Suzhou Setek Co., Ltd. were determined. The results showed that bio-fortification could effectively improve the selenium contents in plants. Selenium content in the tested samples was 0.91–110.8 mg/kg. The main speciation of selenium was selenium amino acid. Selenium in grains and soybeans mainly existed in the form of SeMet (44.2%–80.4%). The main forms of selenium in broccoli were SeMet (27.8%), SeCys₂ (25.9%) and MeSeCys (37.1%). The main forms of Se in Cardamine hupingshanesis were SeMet (73%) and SeCys2 (23.8%). Selenium in Se-enriched plants has high bioaccessibility. The bioaccessibilities were 90% for Se-enriched wheat and soybean, 80% for Se-enriched maize and broccoli, and 50% for Cardamine hupingshanesis, respectively. Se-enriched plants produced by bio-fortification have high selenium content, high organic selenium ratio and good bioaccessibility, thus could be used as important materials for human selenium dietary supplement.