NOVELTY - Method for preparing composition for cultivating Pleurotus citrinopileatus, involves immersing shiitake mushroom powder in purified water, extracting mixture, mixing extract with bagasse, cottonseed hulls and bean cake, stirring and stacking mixture, naturally fermenting the mixture, turning the mixture during fermentation, adding lime and gypsum, continuously fermenting mixture, packaging the fermented product in a polypropylene plastic bag, inoculating the P.citrinopileatus into fermented product, and cultivating the P.citrinopileatus.    USE - The method is useful for preparing composition which is used for cultivating P.citrinopileatus (claimed).    ADVANTAGE - The method prepares composition which is rich in nutritional components e.g. sugars, amino acid, peptide, nucleic acid and trace elements, saves labor, and is environmentally-friendly to perform. The composition exhibits antibacterial effect.    DETAILED DESCRIPTION - Method for preparing composition for cultivating Pleurotus citrinopileatus, involves (a) obtaining 42-48 %mass bagasse, 30-36 %mass cottonseed hulls, 14-16 %mass bean cake, 3-4 %mass shiitake mushroom residues, 2-3 %mass lime and 1 %mass gypsum with respect to 100 %mass of the composition, crushing the bagasse to obtain powder having particle diameter of 3-5 mm, and drying and crushing the shiitake mushroom residues to obtain powder having particle diameter of 2-3 mm, (b) immersing the shiitake mushroom powder in 20-30 times purified water at room temperature for 18-24 hours, extracting obtained mixture, uniformly mixing extract with the bagasse, cottonseed hulls and bean cake, stirring obtained mixture, stacking the mixture to a height of 1-1.2 m and width of 2-3 m, maintaining dry weight of the mixture at 300-500 kg, and naturally fermenting the mixture for 24 hours, (c) turning the mixture during fermentation when the mixture reaches 60 degrees C, adding lime and gypsum, continuously fermenting mixture for 5-6 days, and controlling moisture content of fermented product at 63-65%, and (d) packaging the fermented product in a polypropylene plastic bag having size of 17 cmx 35 cmx 0.004 cm, providing holes in the bag, inoculating the P.citrinopileatus into the fermented product, cultivating the P.citrinopileatus at 18-20 degrees C for 21-23 days until the bag is covered with mycelium, controlling humidity at 60-75% during cultivation, and performing fruiting management.