The invention provides a method for preparing mushroom culturing material. The mushroom culturing material comprises the following compositions by weight percentage: 35 to 55 percent of cotton seed hulls, 25 to 45 percent of rice bran, 10 to 16 percent of bran, 1.5 to 2 percent of bean cakes, 0.5 to 1 percent of lees, 0.5 to 1 percent of peanut shells, 0.5 to 1 percent of gypsum, 1.5 to 2 percent of sorghum husks, 0.1 to 0.3 percent of Sanmate, 0.1 to 0.3 percent of nitrogen phospho potash complex fertilizer, 0.1 to 0.3 percent of oxygenation powder, and 0.5 to 0.8 percent of corn meal. The method comprises the following steps: combining the cotton seed hulls, the rice bran, the bran and the bean cakes together according to the proportion; pouring the mixture into a crushing mill to be crushed into particles with about 120 meshes; adding the lees, the peanut shells, the gypsum, the sorghum husks, the Sanmate, the nitrogen phsopho potash complex fertilizer, the oxygenation powder and the corn meal into the particles according to the proportion after the particles are taken out; and pouring the mixture into a mixer to be mixed for 60 minutes and taken out, adding water according to the proportion of 1:1.3-1:1.5 into the mixture to be evenly piled and fermented for 6 hours to produce a qualified culturing material.