NOVELTY - Cultivation of organic selenium-enriched watermelon involves 1) culturing watermelon seedling using selenium enriched seedling culturing substrate with sowing density of 100 m2/seedling, applying substrate having thickness of 0.5-1 cm to grow seedling; 2) watermelon transplant, before application of organic and inorganic selenium fertilizer as base fertilizer (100-120 kg), 3) watermelon fruit enlargement of organic and inorganic selenium fertilizer applied as additional fertilizer (80-100 kg), and processing mature watermelon to obtain organic selenium-enriched watermelon.    USE - For cultivation of organic selenium-enriched watermelon (claimed).    ADVANTAGE - The method changes the current selenium-enriched watermelon production by normal method by applying selenium-containing solution or selenium foliar fertilizer in watermelon fruit to spray, which avoids the selenium enriched watermelon production in the presence of factors, is economic and provides high efficiency, non-pollution and has positive meaning for improving selenium level, preventing and treating diseases. The method greatly reduces the selenium fertilizer caused by environment pollution, at the same time, changes waste into valuable, and reduces the production cost.    DETAILED DESCRIPTION - Cultivation of organic selenium-enriched watermelon involves 1) culturing watermelon seedling using selenium enriched seedling culturing substrate with sowing density of 100 m2/seedling, applying substrate having thickness of 0.5-1 cm to grow seedling; 2) watermelon transplant, before application of organic and inorganic selenium special fertilizer as base fertilizer (100-120 kg), 3) watermelon fruit enlargement of organic and inorganic selenium special fertilizer applied as additional fertilizer (80-100 kg), and processing the mature watermelon to obtain organic selenium-enriched watermelon. The selenium-enriched seedling culturing substrate is prepared by mixing pagoda (30-50 parts by weight), selenium containing rice hull (20-40 parts by weight), fermented chicken manure (10-30 parts by weight), and river sand (10-20 parts by weight), and mixing by farmyard manure stack anger or factorial compost. The selenium-enriched organic and inorganic special fertilizer is prepared by selenium-containing pagoda (30-70 parts by weight), nitrogen fertilizer (11-13 parts by weight), phosphate fertilizer (6-8 parts by weight), potassium fertilizers (9-11 parts by weight) and micro-element (0.5-1).