NOVELTY - Forming an organic selenium-rich mixed fertilizer involves mixing livestock and poultry dung, humic acid, mycelium mixed amino acid mother liquor, probiotics, compound containing microelement selenium and zinc, and water, with match material such as nitrogen, phosphorus, potassium fertilizer, high strength of absorbent polymers, crop straw and stevia slag, followed by stirring and mixing in biological reactor, reducing moisture below 40%, after fermentation and dehydration, and smashing to 50-75 meshes of prilling.    USE - For the preparation of an organic selenium-rich mixed fertilizer which is useful for producing functional agricultural products (claimed) such as selenium-rich rice, selenium rich wheat and selenium-rich tea.    ADVANTAGE - The fertilizer is capable of being used to produce functional agricultural products containing beneficial trace elements; increases crop output by 10-50%; and achieves the requirements of the national selenium-rich agricultural products with the possibility of achieving 100-500 mu g/kg selenium content of products.    DETAILED DESCRIPTION - Preparation of an organic selenium-rich mixed fertilizer for producing agricultural products involves: taking livestock and poultry dung (65-70%), humic acid (10-15%), mycelium mixed amino acid mother liquor (5-10%), probiotics (dissolving e.g. potassium, phosphorus, methanobacteria, actinomycetes and nitrobacterium), compound (2-5%) containing microelement selenium and zinc and 95% of the total amount of water is controlled within at 60 degrees C, adding proper superphosphate to adjust pH within 7.5-8, adding multifunction inoculums in the organic material for mixing, then adding the match material such as nitrogen, phosphorus and potassium fertilizer, high strength of absorbent polymers, crop straw and stevia slag, stirring and mixing in the biological reactor at the mixing and fermentation temperature of 25-60 degrees C within 35 days, reducing the moisture below 40%, lowering pH to 7, where inorganic selenium and zinc are converted into organic selenium and zinc (amino acid selenium and zinc) which is easily absorbed by crop after fermenting, adding proper carbon source in the mixed dumps of the organic material in order to make the functional bacterium balanced in nutrition, carbon/nitrogen ratio of the organic material after mixing is controlled with 30-40 because of the smashed straw or urea nitrogen source, after drying (moisture is less than 17%), it is smashed into 50-75 meshes prilling by mixing with urea, superphosphate and potassium chloride.