The invention discloses a treatment method for liquid waste produced during acid-process preparation of aluminum oxide. The treatment method comprises the following steps: S1, carrying out spray roasting on the liquid waste to obtain a first acidic gas and primary iron ore powder; and S2, recovering the first acidic gas and purifying the primary iron ore powder. According to the technical scheme disclosed by the invention, firstly, the liquid waste is subjected to spray roasted, so as to obtain the first acidic gas and the primary iron ore powder; the first acidic gas is recovered and the primary iron ore powder is purified, so that the acid in the liquid waste is recycled by recovery of the acidic gas. Iron and aluminum ions in the liquid waste are recovered by purification of the primary iron ore powder. Thus, the treatment method can be made into industrial products, resource utilization is maximized, and secondary pollutants are hardly generated.