NOVELTY - Fodder yeast is prepared by mixing glucose mother liquor with waste liquid from phytin extraction, controlling the concentration of sugar to 1.5-3%, and adjusting pH value to 4-6 with ammonia water to obtain fodder yeast culture medium; cultivating yeast strain to obtain seed liquid; pumping the prepared yeast culture medium into a self-suction fermenter, inoculating the seed liquid into the self-suction fermenter at 28-32 degrees C for 8-12 hours; evaporating and concentrating the liquid; and spraying and drying the evaporated fermentation broth.    USE - Method for preparing fodder yeast (claimed).    ADVANTAGE - The method optimizes use of resource such that the waste material is recycled; is environment-friendly; and improves additive value of the product.    DETAILED DESCRIPTION - Preparation of fodder yeast comprises:    (A) preparing fodder yeast culture medium using glucose mother liquor (42-50%) and reducing sugar with content of not less than 80%; extracting phytin from corn soaked in water until the waste liquid is clear and transparent and pH value is 5.8-6, and after ion exchanging, reducing the ash content and pH value; mixing the glucose mother liquor with the waste liquid after extracting phytin, controlling the concentration of the sugar to 1.5-3%, and adjusting pH value to 4-6 with ammonia water for later use;    (B) selecting yeast strain, cultivating in a shaking bed after slant cultivation at 28-32 degrees C for 10-14 hours to obtain primary seed liquid, in which when the cultivation is finished, the residual sugar is not greater than 0.5% and optical density (OD) value is 1.2-1.35; inoculating the fermentation broth in the shaking bed into a fermenter, amplifying and cultivating secondarily to obtain secondary seed liquid;    (C) pumping the prepared yeast culture medium into a self-suction fermenter, inoculating the secondary seed liquid into the self-suction fermenter at 28-32 degrees C for 8-12 hours, where the inoculum size is 10-20%, the content of sugar is controlled at 1.5-3%, the vent ratio is 1:0.5-1, and where after finishing cultivation the OD value is 1.6-1.8, the residual sugar is not greater than 0.5%;    (D) evaporating and concentrating the liquid after finishing fermentation with a waste-heat evaporator or a triple-effect evaporator to obtain fermentation broth concentration of 15-40%; and    (E) spraying and drying the evaporated fermentation broth in a high-speed centrifugal spray drying tower.