The invention provides a technology for preparing acid and coproducing a ceramic cutting tool by using phosphor gypsum and coal ash. The technology comprises the following steps: mixing and grinding phosphor gypsum, coal ash, an additive and a modifier into a raw material, feeding the raw material into a kiln for roasting to obtain a cooked material; dissolving the obtained cooked material, and carrying out solid-liquid separation; floating a residue obtained through separation to obtain a sulfide through separation; treating the sulfide to obtain sulfuric acid; preparing the solution obtainedthrough separation into high purity alumina powder; uniformly mixing the high purity alumina powder with zirconium oxide, titanium oxide, barium carbonate, LiSbO3, potassium-sodium niobate, cerium oxide, lanthanum nitrate, carboxymethylcellulose, nickel carbonyl powder, borax, sodium humate, polyacrylic acid, polyethylene glycol and an abrasion-resistant accessory ingredient to obtain the ceramiccutting tool. The technology has the characteristics that the cost of acid preparation and ceramic cutting tool preparation is low, the utilization rate of a waste residue is high, the technology issimple and the ceramic cutting tool material prepared by using the high purity alumina powder is high in rigidity, good in abrasion resistance, high in bending resistance and high in tenacity.