ZnO thin films were prepared on indium-tin oxide (ITO) substrates by pulsed current electrolysis. The preferred orientation of the ZnO thin films prepared by pulsed current electrolysis changed in order to (0002), (10 (1) over bar1), and (1010) by the change in overvoltage. Green-yellow emission centered around 580 nm was observed for the ZnO films. The increase of intensity of the green-yellow emission may be ascribed to effects brought about during the pause of electrolysis. The transmittance at 600 nm for ZnO thin films prepared by pulsed current electrolysis was over 95%. It was demonstrated that pulsed current electrolysis is effective for control of preferred orientation and concentration of lattice defects and for improvement of the transmittance of ZnO thin films.