Zinc oxide (ZnO) and Zirconium (Zr) doped ZnO nano films have been successfully fabricated by radio frequency (RF) magnetic sputtering. The crystal structure and morphology were investigated by X-ray Diffraction (XRD), Field Emission-Scanning Electron Microscope (FE-SEM) and Transmission Electron Microscope (TEM). As the doped Zr content increases, ZnO nano films show various morphologies. The optical band gap of pure ZnO films increases from 3.27 eV to 3.53 eV with Zr concentration increasing to 9.66 at.%. After annealing, the polycrystalline structure of ZnO changes a little and the energy gap decreases. In addition, the clean and lower doped ZnO films show much lower transmittance.