The invention discloses expanded feed for resisting the fatty liver of tilapia and a preparation method of the expanded feed. The feed is prepared from, by mass, 3% to 8% of domestic fish meal, 15% to 25% of bean pulp, 15% to 30% of double-low rapeseed meal, 10% to 15% of cottonseed meal, 15% to 23% of strong flour, 8% to 15% of corn, 6% to 12% of DDGS, 1% to 2% of freshwater fish oil, 1% to 3% of soybean oil, 1% to 2% of monocalcium phosphate, 1% to 3% of bentonite, 1% to 2% of premix of vitamin and mineral salt, 0.1% to 0.5% of crystalline lysine, 0.1% to 0.5% of free methionine and 1% to 2% of compound fatty liver resisting preparation. Through reasonable component matching, all the nutritional requirements of tilapia are met, the stability of the feed in water is good, the tilapia grows fast, the feed conversion rate is high, and the survival rate is high. Meanwhile, according to the feed, the secretion and metabolic capability of the liver cells of the tilapia can be obviously improved, the liver function and disease resistance of the tilapia can be improved, the organ-body ratio and the fat-body ratio can be decreased, the meat taking rate can be increased, and culture benefits are good.