Abstract: ZnO thin films with high c-axis orientation were prepared on polished Si ＜111＞ substrates by using spin coating method. DSC and XRD tests show that the optimal heat-treatment temperature for the sol-gel system to form ZnO film is about 450℃. The disadvantage influence on orientation can take place for higher temperature. Surface morphologies of the films were investigated by SEM, which show the high c-axis orientation of grains with average size of 50~100 nm.