Abstract: Zinc oxide（ZnO） with average particle size of 60 nm was prepared by liquid precipitation method with zinc sulfate and sodium carbonate as raw materials.The optimum technological conditions to prepare nanometer ZnO were obtained through orthogonal experiment.The particle size distribution，thermal performance，crystal shape structure，and micro-morphology were characterized by physical methods of laser particle size analysis，thermo-gravimetric analysis（TG-DTA），X-ray diffraction analysis（XRD），and scanning electron microscope（SEM）.Results showed that： the grain size of the products was well-distributed with good dispersivity，and the average particle size was 60 nm；the precursor calcining temperature was 400 ℃，morphology was spherical or spherical-like.Photocatalytic experiments were made with nanometer ZnO as photochemical catalyst，for degradation of acidic magenta and methyl orange，and results showed that: the photocatalytic ability of nanometer ZnO was quite strong，and the degradation rates of acidic magenta and methyl orange were 98.75% and 92.37%， respectively.

Key words: Nanometer ZnO, Liquid precipitation, photocatalysis, degradation