Zirconium oxychloride, urea and ammonia have been used to produce the precursor by the precipition method. The precur' sor was heat-treated to obtain the zirconia powders. Differential thermal analysis shows that the precursor changes into amorphous zirconia at 300C, and then transforms to tetragonel zirconia at 450C. The processes are endoergic and exoergic, respectively. XRD analysis shows that the monoclinic zirconia not can be obtained below 700C. The content of monoclinic zirconia increases as the calcination time increases. The zirconia powders so obtained are nanostructured. The size of the powders increases quadratically with the calcination temperature. The particle size increases linearly with calcination time.Correspondent: Liao Shuzhi, Doctor, Associate Professor, Department of Physics, Hunan Educational institute, Changsha 410012,P. R. China, Tel: 086 - 731 - 8826401