Abstract <p>Selenium (Se) is a vital element of increasing significance and is crucial for human health. why chrysanthemum is being studied, because Chuju is one of the chrysanthemum varieties, its selenium content is significantly higher than others. Herein, we did field experiments where selenate and selenite were applied to the soil. In this research, the content of Se in rhizosphere soil and various organs of Chuju was determined using ICP-MS. Se speciation in different organs of Chuju was analyzed through HPLC-ICP-MS. Our findings revealed that treatments with selenate and selenite in soil increased both the Se content and bioconcentration factor in various organs of Chuju when compared with the control. Besides, treatment with selenate enhanced the translocation factor in different organs of Chuju. Conversely, while treatment with selenite resulted in an increased translocation factor for stems/roots, there was a decrease in the leaf/root and inflorescence/root ratios. In genuine producing areas of Chuju, Se predominantly existed as selenomethionine (SeMet), with its speciation influenced by the source of Se. Following the application of selenate, Se in Chuju was mainly transported from roots to above-ground parts as either Se(VI) or SeMet; after applying selenite, it was converted into SeMet and other organic selenium mainly within the roots before being transported upward as organic selenium, and its transport capacity was lower than that of selenate treatment. Finally, the Se biofortification may notably enhance Se levels in Chuju, and the effect of selenate application is better than selenite.</p>