Abstract: Nanometer zinc oxide was synthesized by the homogeneous precipitation method　from zinc chloride and sodium carbonate.The affecting law of preparation conditions on nanometer zinc oxide particle size and morphology was investigated by laser particle size analyzer and TEM etc..The optimum process conditions were found as follows：the initial Zn2+ concentra- tion was 0.74 mol/L，c（CO32-）/c（Zn2+）=1.1，the reaction time was 40 min，the reaction temperature was 90 ℃，the calcina- tion temperature was 600 ℃，and the calcination time was 1 h.Under these conditions nanometer zinc oxide had spherical morphologies，uniform granularity，and good dispersivity with particles size of 25 nm and second particle size（D50） of 549.9  nm.The study results can provide basic data for studying team to industrially produce nanometer zinc oxide in low cost.

Key words: nanometer zinc oxide, morphology, second particle size, process conditions