Na-Mg co-doped ZnO thin films using zinc acetate,magnesium nitra te and sodium acetate as a precursor solution were successfully prepared on quartz substrate by ultras onic spray pyrolysis method at different substrate temperatures (480℃－560℃).The struct ural,surface morphological,photoluminescence (PL) and transmission properties of the samples were investigated by X-ray diffraction (XRD),scanning electron microscope (SEM),PL spectrum and ultraviolet-visible UV-Vis spectrophotometer.The results demonstrate that the substrate temperature has important effects on structural and optical characteristics.The sample prepared at 500℃ owns the better c-axis preferential orientation,the more den se surface morphology,the better crystalline quality and the optimum PL properti es.