NOVELTY - Preparation method of selenium-rich organic fertilizer involves (a) fermentation culturing of Flammulina velutipes, (b) inoculating medium with culture, and adding selenium species to culture, (c) collecting cells and drying, (d) stacking compost mixture of e.g. sheep manure and allowing to stand, (e) mixing, stacking and leaving compost for 3 days, (f) crushing dried cells and mixing with compost, (g) adding fermentation material and carrying out fermentation of mixture, (h) adding e.g. kaolin to fermented mixture and sieving mixture, (i) packing product.    USE - Preparation method of selenium-rich organic fertilizer (claimed).    ADVANTAGE - The prepared fertilizer has improved selenium content and has good economic benefits.    DETAILED DESCRIPTION - Preparation method of selenium-rich organic fertilizer involves (a) fermentation culturing of Flammulina velutipes by culturing mushroom for 5 days, as mushroom of higher classification has selenium-enriching transformation ability, (b) inoculating fresh solid slope medium with low concentration of domesticated F.velutipes culture obtained in step (a), and adding suitable amount of selenium species to the liquid fermentation culture, (c) collecting cells from the culture and drying, (d) mixing sheep manure, chicken manure, soybean meal, rice bran and pond sludge to obtain compost, stacking compost to 1.5-2 m height, and leaving the compost for 10 days, (e) mixing compost, stacking and leaving the compost for 10 days, again mixing compost, stacking and leaving the compost for 10 days, and again mixing compost, (f) crushing F.velutipes dried cells obtained in step (c) and mixing with the compost obtained in step (e), (g) adding fermentation material and carrying out fermentation of mixture obtained in step (f), (h) adding humic acid and trace elements, kaolin, mica powder, slaked lime and borax to fermented mixture and uniformly mixing, crushing and sieving mixture to obtain powder product, (i) granulating the powder product, and (j) packing product.