The invention provides a method for growing selenium-enriched wheat seedlings by dynamic gradient thorough selenium enrichment, which comprises: repeatedly and alternatively soaking wheat seeds in base culture solution and selenium-containing culture solution; and cutting off from the part which is 1 centimeter away from the root of the wheat seedlings after the seedlings of the wheat grow come out for 13 to 18 days and grow to 10.5 to 16 centimeters. In order to adapt the growth process of the wheat seedlings to the selenium enrichment process gradually, the method adopts the base culture solution and the selenium-containing solution to culture the wheat seedlings repeatedly and alternatively and constantly changes the selenium concentration in the selenium-containing culture solution, thereby enriching a large amount of organic selenium in the wheat seedlings and improving the emerge rate of the wheat seedlings, seedling rate and yield. According to test, the total selenium content of the selenium-enrich wheat seedling products is 18 to 24mg/kg and the organic selenium content is 16 to 21.5mg/kg; and compared with the wheat seedlings grown by thorough base culture solution culture, the selenium enrichment times increases to 6 to 8 times, the organic selenium conversion rate reaches 80 to 90 percent, the emerge rate is increased by 20 to 30 percent, and the seedling rate is increased by 60 to 95 percent.