The invention relates to a method for the comprehensive utilization of calcium-silicon slag, which comprises the following steps: preparing an acidic correction liquor; mixing the calcium-silicon slag and the acidic correction liquor for a leaching reaction, and then carrying out solid-liquid separation to obtain aluminum-containing slag and a leaching liquor; and washing the aluminum-containing slag until the pH value of the washing liquor reaches 7, mixing the aluminum-containing slag and a sodium hydroxide solution for a digestion reaction, carrying out solid-liquid separation again, and carrying out carbonation decomposition on the obtained digestion liquor to obtain aluminum hydroxide. The method for the comprehensive utilization of the calcium-silicon slag perfectly realizes the completely comprehensive utilization of the calcium-silicon slag, extends the industrial chain of aluminum oxide, and can be used for producing calcium chloride products which have large capacity of the market, thus providing the foundation for the popularization of the technology.