Abstract: Crystallized aluminum hydroxide was successfully prepared by neutralizing aluminum oxide and amorphous Al（OH）₃, which stem from the aluminum mud deposits pole of aluminum allay products, with base, and then by hydrolyzing with CO₂. The effects of temperature, acidity and CO₂ flow rate on the yield of crystallized Al（OH）₃ were investigated. The optimum conditions for the preparation of crystallized Al（OH）₃ were temperature 70～ 80 ℃ , pH 8～9, CO₂ current rate 50～60 mL/min and under strong stirring. The research achieves recovery of aluminum resources, purifying of the environment, and recovery of byproduct Na₂CO₃, thus making the waste into valuable resources without secondary pollution.