The invention relates to mushroom compost, which consists of the following components in percentage by weight: 35 to 55 percent of soya bean stem meal, 25 to 45 percent of peanut shell, 10 to 16 percent of sorghum flour, 1.5 to 2 percent of dry duck manure, 0.5 to 1 percent of rape stalk, 0.5 to 1 percent of urea, 0.5 to 1 percent of lime, 1.5 to 2 percent of rabbit manure, 0.1 to 0.3 percent of magnesium sulfate, 0.1 to 0.3 percent of organic compound fertilizer, 0.1 to 0.3 percent of oxygen-increasing powder, and 0.5 to 0.8 percent of mepartricin liquid. A method for preparing the mushroom compost comprises the following steps of: completely combining the soya bean stem meal, the peanut shell, the sorghum flour, the dry duck manure, the rape stalk and the rabbit manure according to the proportion, pouring the mixture into a grinder to grind the mixture into particles of about 120 meshes, and taking the particles out; adding the urea, the lime, the magnesium sulfate, the organic compound fertilizer, the oxygen-increasing powder and the mepartricin liquid according to the proportion, pouring the mixture into a stirrer to stir the mixture for 60 minutes, and taking the stirred mixture out; adding water in an amount which is 1.1 to 1.2 times the weight of the mixture, uniformly mixing, and stacking to perform fermentation for 10 hours to obtain the qualified compost.