Microstructures　and　mechanical　properties　of　zinc　oxide　(ZnO)　thin　films　deposited　onto　glass　substrates　by　rf　magnetron　sputtering　were　studied.　Surface　morphologies　and　crystalline　structural　characteristics　were　examined　using　atomic　force　microscopy　(AFM)　and　X-ray　diffraction　(XRD),　respectively.　Mechanical　properties　were　measured　by　nanoindentation.　The　crystalline　structures　of　ZnO　thin　films　were　well　ordered　with　high　c-axis　(002)　orientations.　The　surface　morphologies　of　ZnO　thin　films　were　smooth　and　grains　grew　and　distributed　uniformly.　A　single　pop-in　in　the　load-displacement　curve　was　clearly　observed　at　a　specific　depth　(7-10nm)　of　the　thin　film.　The　hardness　and　Young＇s　modulus　of　ZnO　thin　films　were　ranged　from　8.2　to　10.4GPa　and　105　to　120GPa,　respectively.　©　2009　Copyright　SPIE　-　The　International　Society　for　Optical　Engineering.