Abstract: Spinel-type CuAl₂O₄ powder was prepared by sol-gel method with copper nitrate, copper chloride, and copper sulfate as raw materials, respectively. The phase composition, photocatalytic property and microstructure of the powder were studied by X-ray diffractometer, photocatalytic reactor, infrared spectroscope and X-ray photoelectron spectrometer. The results show that the CuAl₂O₄ powder, prepared at 700 ℃ with copper sulfate raw material added with 20 mL ammonia, had the best photocatalytic property, and the degradation rate of methyl orange was 90%. There was Cu₂O(SO₄) phase in the CuAl₂O₄ powder prepared with raw material of copper sulfate. The Cu₂O(SO₄) phase improved the photocatalytic property of CuAl₂O₄ powder.