Zinc oxide thin films were prepared on the glass substrate by rf-magnetron sputtering technique and their structural, optical, and mechanical characteristics were then investigated. As the SEM images have revealed, the average grain size of ZMO thin film are influenced by pressure and sputter power, and the average value of the grain size is about 30∼50 nm. The EDS analysis also revealed a successful doping of Mo in ZnO thin film. The transmittance property of ZMO thin film exhibited an excellent transparency in the visible range, where the transmittance was about 90% for ZMO film with Mo. Moreover, good transmittance was also demonstrated in the range of 350nm to 400nm (UV regime). Finally, the nano-mechanical properties of ZMO thin films were investigated using a nanoindentation technique. The corresponding result would show that the Young's modulus and hardness both increased with decreasing pressure.