The invention discloses a method for producing industrial activated aluminum oxide from pulverized fuel ash, comprising the following steps: mechanically activating the pulverized fuel ash, floating and removing carbon, magnetically selecting and removing iron, impregnating in sulfuric acid to extract aluminum, separating solid and liquid, condensing rough liquid of aluminum sulfate, re-crystallizing aluminum sulfate, separating solid and liquid for the second time, dehydrating and drying aluminum sulfate, and calcining aluminum sulfate at a high temperature so as to obtain the industrial activated Al2O3 in which the content of Fe2O3 is lower than 0.5%; and the method completely meets the technical requirement of HG/T3927-2007 industrial activated aluminum oxide. The method is simple in technique, short in flow, easy to control production process, high in aluminum oxide extract rate, low in production cost, low in impurity content, and stable in quality.