NOVELTY - Storing and reducing Agaricus bisporus cultivation material after fermentation involves first time fermenting by wetting matched raw material; producing compost by micro-organism activity at 60-80 degrees C; second time fermenting; drying the compost; storing the compost; reducing the compost by adding water into stored compost to deoxidize, adding clean limewater, adjusting water content, piling the compost and covering with plastic film; sterilizing the compost; and cooling the compost to sow.    USE - Method for storing and reducing Agaricus bisporus cultivation material after fermentation.    ADVANTAGE - The method is capable of improving utilization of device and resolves the need (supply) compost in the production season.    DETAILED DESCRIPTION - Storing and reducing Agaricus bisporus cultivation material after fermentation involves:    (A) first time fermenting by wetting matched raw material; producing compost by micro-organism activity at 60-80 degrees C;    (B) second time fermenting by controlling temperature and air in cultivation room, fermenting to decompose at 45-55 degrees C by high temperature actinomycetes and performing temperature balancing, sterilizing, mulling, and cooling four section;    (C) drying the compost at lower than 70 degrees C to store the compost after the second time fermentation;    (D) piling in a drying place for storing by bagging, bundling or bulking;    (E) reducing the compost by adding water into stored compost to deoxidize, adding clean limewater with pH 8.5, adjusting the water content to 62%, piling the compost to a height of 1.3-1.5 cm and width of 2.3-2.5 meter, and covering with plastic film, in which the piling time is 2-3 days;    (F) sterilizing the compost, spreading onto bedstead of mushroom room, and sterilizing;    (G) raising room and compost temperatures to 58-62 degrees C for 6-8 hours;    (H) sealing the mushroom room for 24 hours after sterilization;    (I) cooling the compost to sow;    (J) opening the mushroom room to draught;    (K) spraying a little clear limewater with pH of 8-9 on the compost surface layer; and    (L) sowing.