The invention discloses a special selenium-enriched organic fertilizer for agaric and relates to the field of fertilizers. The organic fertilizer specifically comprises the following raw materials: chicken manure, duck manure, pig manure, selenium-enriched corncob, wheat bran, bean dregs, humic acid, bone meal, scoria, lotus seed skin, garlic, mangosteen fruit skin, lycium ruthenicum residues, selenium-enriched waste tea leaves, overdue milk and purple sweet potatoes. A preparation method of the special selenium-enriched organic fertilizer for agaric comprises the following steps: (1) pretreating the raw materials; (2) mixing and stirring; (3) performing composting fermentation; and (4) bagging and sterilizing. The special selenium-enriched organic fertilizer for agaric disclosed by the invention is prepared from raw materials readily available and is rich in nutritional ingredients, the yield of agaric can be improved, and the harvested agaric is rich in selenium.