ZnO is an n-type semiconductor having a hexagonal wurzite structure. ZnO exhibits good piezoelectric and optical properties, and might be a good candidate for an electroluminescence device like an UV laser diode. Then, these devices are very small, their films are very thin and they are prepared in the limited size and shape, so they are unsuitable for the extensive mechanical testing. In this present work, ZnO thin films are prepared on the glass, GaAs(100), Si(100) and Si(111) substrates at various temperatures by the pulsed laser deposition (PLD) method. ZnO thin films were evaluated by X-ray diffraction (XRD) and mechanical properties such as hardness and elastic modulus were measured through the nano-indenter.