Abstract: Highly C-axis oriented ZnO thin films were prepared by high-vacuum RF magnetron sputtering technique.The effect of annealing temperatures on the surface morphology and residual stress of ZnO thin film was studied by SEM and XRD.Results show that the surface morphology and residual stress of appropriately annealed film are improved.By introduction of oxygen,heat activation of defect atoms and combination of small grains,the tensile stress in the film induced by heat effect,defect effect and inpouring effect of particles decreases significantly.The grain microconstituent is compacted and the orientation of crystal-grain-columns increases.The minimum residual tensile stress and the optimal crystalline quality of ZnO thin film are obtained by being annealed at 450℃.