The invention discloses a method for preparing feedstuff for ctenopharyngodon idellus. Preparation raw materials for the feedstuff comprise the following ingredients in parts by mass: 30-35 parts of rapeseed cakes, 26-31 parts of peanut shell powder, 30-35 parts of corn protein powder, 10-15 parts of bovine vertebrae, 15-20 parts of tunas, 7-9 parts of Sudan grass, 4-5 parts of lolium perenne, 5-7parts of Pham Thanh Thao, 10-15 parts of rapes, 10-15 parts of Chinese cabbages, 5-6 parts of malt, 0.1-0.5 part of fat emulsifier and 5-7 parts of adjuvants, wherein the adjuvants are prepared fromthe following raw materials in parts by weight: 10-15 parts of rice, 2-6 parts of flos chrysanthemi indici, 5-7 parts of basil seeds, 7-9 parts of brown sugar, 2-3 parts of diatomite and 1-2 parts ofrhizoma zedoariae. Mixed protein powder and meat and bone meal are mixed, the corn protein powder contains relatively low lysine and arginine, the meat and bone meal contains relatively high lysine and arginine, the corn protein powder and the meat and bone meal are fed in a mixed manner, then, a supplementary action is exerted, essential amino acids can be balanced, and thus, the utilization ratio of proteins is increased; and the fat emulsifier can be used for lowering occurrence of diseases such as fatty liver and meanwhile preventing abdominal fat deposition and promoting growth of the ctenopharyngodon idellus, and the obtained income is higher.