Direct precipitation was used to prepare nano zirconia in this experiment. The influences of five experimental parameters upon the mean size, yield and dispersity of the product were investigated via uniform design. These parameters were molar ratio of NH3 center dot H2O to ZrOCl2, C2H5OH percentage in reacting and washing solutions, ZrOCl2 concentration, precipitation temperature and surfactant PEG-800 dosage. The condition experiments demonstrated that C2H5OH played a significant role in improving the dispersity of the product in the absence of surfactant PEG-800 and the higher the C2H5OH percentage, the better the dispersity. By using C2H5OH to dissolve ZrOCl2 center dot 8H(2)O and conc. NH3 center dot H2O respectively and mixing them, we carried out the precipitation in the C2H5OH medium to generate hydroxide precursor, which was filtrated, washed with C2H5OH, dried and calcined to form well-dispersed uniform nano zirconia. (c) 2006 Elsevier B.V. All rights reserved.