Transparent　zinc　oxide　(ZnO)　films　were　prepared　on　ZnWO4　crystal　by　sol-gel　technique.　Surface　morphology　of　ZnO　films　were　observed　with　optical　microscope.　The　results　of　show　that　ZnO　films　are　formed　in　three　different　stages　from　nucleation　on　surface,　grain　growth　to　island　formation.　Because　ZnO　crystal　nucleus　were　grown　under　non-equilibrium　condition,　it　is　inevitable　that　dendrite　growth,　fractal　growth　and　spinodal　decomposition　phenomenon　are　involved　in　the　growing　process.