ZnO particles doped with 0 mol％-5 mol％ Cd dopant were successfully synthesized by a precipitation method.The as-synthesized products were characterized by thermogravimetric analysis (TGA),differential scanning calorimetry (DSC),X-ray diffraction (XRD),photoluminescence (PL) spectroscopy,Raman spectroscopy,scanning electron microscopy (SEM) coupled with an energy-dispersive X-ray (EDX) spectroscopy and transmission electron microscopy (TEM).The precursors showed weight loss at 35-700 ℃ caused by phase transformation and evaporation processes.The as-synthesized products were specified as hexagonal wurtzite ZnO.The crystallite size of ZnO samples doped with 0 mol％-5 mol％ Cd gradually increased with the increase in Cd content.The photocatalytic activities of 0 mol％-5 mol％ Cd-doped ZnO samples were evaluated through photodecolorization of methylene blue (MB) under ultraviolet (UV) radiation.In this research,ZnO doped with 3 mol％ Cd shows the best photocatalytic activity in degrading of MB molecules as much as 89％ within 240 min.