The invention discloses a modified scaling inhibitor. The scaling inhibitor is prepared by usingthe following raw materials in parts by weight: 50 to 80 parts of polyaspartic acid, 30 to 50 parts of polyepoxysuccinic acid, 8 to 10 parts of sodium gluconate, 5 to 10 parts of glycerol, 20 to 30 parts of ethanol, 0 to 15 parts of acidity regulator, 0 to 15 parts of alkalinity regulator, 5 to 8 parts of benzotriazole, 5 to 10 parts of zinc sulfate, 20 to 30 parts of modifier, 10 to 20 parts of assistant and 70 to 90 parts of water. In the modified scaling inhibitor, by compounding and proportioning polyepoxysuccinic acid and polyaspartic acid, the amount of used polyepoxysuccinic acid is reduced, the production cost is decreased, the application scope is widened, the comprehensive performance is improved, the proportioning of zinc sulfate and sodium gluconate improves the stability of water quality and can maintain the high corrosion-inhibiting rate under high-temperature conditions, the steps of the method for preparing the modified scaling inhibitor are simple, the time is saved and the performance of the prepared modified scaling inhibitor is excellent.