Zinc oxide (ZnO) and Dysprosium (Dy) doped ZnO nano films have been successfully prepared by radio frequency (RF) magnetron sputter. Then the crystal structure, morphology and optical of the films were investigated. All the samples have a preferred orientation with the (0 0 2) orientation perpendicular to the substrates. The surface morphology of the films changes greatly with the increasing of doping content. Agglomeration appears when the doping content is excess, which may result from the recrystallization of the small crystalline grain. The average transmittance in the visible range all exceeds 80% for the different doping content ﬁlms and the band gap increases from 3.26eV to 3.34eV.