NOVELTY - Soil-less cultivation to increase organic selenium content in okra comprises e.g. taking crop straw, smashing, taking animal urine, industrial and agricultural by-product and silicon dioxide, mixing, obtaining substrate material, fermenting substrate material, turning once, obtaining decomposed organic matter, mixing decomposed organic matter and sand uniformly to obtain soilless cultivation substrate containing nano selenium, seedling selection, moving seedling in the greenhouse planting groove, filling soilless cultivation substrate containing nano selenium, compacting, and watering.    USE - The method is useful for soil-less cultivation to increase organic selenium content in okra (claimed).    ADVANTAGE - The method can obviously increase yield of okra, has good economic benefit, reduces use of fertilizer and pesticide, is economical, is environmentally friendly and produces non-polluted product, and is suitable for large-scale popularization. Okra is nutritious and has health-care value.    DETAILED DESCRIPTION - Soil-less cultivation to increase organic selenium content in okra comprises (i) preparing soilless cultivation substrate: taking 250-400 pts. wt. crop straw, smashing to length of 0.5-2 cm, taking 100-200 pts. wt. animal urine, 100-500 pts. wt. industrial and agricultural by-product, and 0.1-0.5 pts. wt. silicon dioxide, mixing uniformly, obtaining substrate material, fermenting substrate material at 28-35 degrees C, every 12 hour turning once, after 14-21 days, when substrate material show red nano selenium, ending fermentation, obtaining decomposed organic matter, mixing decomposed organic matter and 400-1000 pts. wt. sand uniformly to obtain soilless cultivation substrate containing nano selenium, (ii) seedling selection: taking height of 6-10 cm robust okra seedlings, using 0.3-0.6% potassium permanganate solution, soaking the roots of okra seedlings for 2-6 minutes, cleaning with clean water, and airing, (iii) planting: moving seedling in the greenhouse planting groove, filling soilless cultivation substrate containing nano selenium, compacting, where the thickness of soil-less cultivation substrate is 20-25 cm, and watering, and (iv) management: pruning okra, disease preventing and treating and prompting retention management, after ripening to fruit, picking process, obtaining organic selenium content enriched okra.