To provide a process for producing an aluminum oxide powder, whereby the content of impurities is controlled by a physical means. A process for producing an aluminum oxide powder, which comprises pulverizing electrofused alumina by a batch system and classifying the obtained pulverized product to obtain an aluminum oxide powder different in the content of impurities. It is possible to obtain aluminum oxide of high purity by pulverization to a smaller average particle size and separating a powder having a larger average particle size by classification.