Abstract: Taking six-month-old, one-year-old and two-year-old Dendrobium officinale seedlings as experimental materials, experiment of applying exogenous selenium fertilizer was adopted to study the effects of different forms of exogenous selenium（liquid selenium fertilizer SA and SJ,solid selenium fertilizer SD） on the selenium enrichment capacity of Dendrobium officinale seedlings planted in the house.Spraying after sampling for 1 time every 2 months, and spraying 6 times in a row, and the total selenium value of fresh strips of Dendrobium officinale was measured in half a year.In order to provide a reference for the standardized production of selenium enrichment of Dendrobium officinale in Guangxi.The results showed that the selenium content of fresh strips of Dendrobium officinale was significantly increased by applying exogenous selenium fertilizer,and the younger the seedling age of Dendrobium officinale,the stronger its ability to absorb exogenous selenium.