The invention provides a method for recovering indium from an indium-contained sulfuric acid solution and copper ash. The method comprises: A, leaching: adding the copper ash into the indium-contained sulfuric acid solution for leaching, then adding water, continuing to leach, and separating to obtain leached slag and a leachate; B, purifying: adding iron power into the leachate obtained in the step A, reducing valuable metal ions in the leachate into metal, enriching the metal into the slag, and then separating to obtain a purifying solution; C, extracting: conducting conventional extraction on the purifying solution obtained in the step B to extract indium, and then conducting replacement, briquetting and casting to obtain crude indium. The method provided by the invention directly adopts the indium-contained sulfuric acid solution to leach the copper ash, fully utilizes sulfuric acid and chlorine in the indium-contained sulfuric acid solution, and has the advantages of simple process, high indium recovery rate, low product cost, enrichment of valuable metals of copper, bismuth, tin and the like.