In　this　paper,　the　high　temperature　solid　state　reaction　method　was　applied　to　the　preparation　of　SrTiO3　ceramic　target.　The　phase　of　the　target　has　been　researched　in　experiment　by　X-ray　diffraction　(XRD).　We　found　that　solid　state　reaction　has　achieved　completely.　Then　SrTiO3　thin　films　on　MgO　(100)　substrate　were　manufactured　by　PLD　using　the　triple-frequency　harmonics　of　pulsed　laser　Nd:YAG.　The　thickness　of　the　SrTiO3　thin　films　was　measured　using　a　stylus　profiler.　Their　microstructure　and　surface　morphology　were　analyzed　using　X-ray　diffraction　(XRD)　and　atomic　force　microscopy　(AFM).　Their　optical　character　was　characterized　using　optical　transmission　spectrum.　Additionally,　X-ray　photoelectron　spectroscopy　(XPS)　spectra　were　used　to　characterize　the　surface　chemical　composition　of　the　SrTiO3　thin　film.　In　accordance　with　the　above　text　result,　the　relation　between　the　substrate　temperature　and　the　SrTiO3　thin　films＇　the　structure　and　character　was　analyzed　and　discussed.　With　increasing　temperature　of　the　substrate,　film　grain　size　gradually　increased　and　then　smaller.　The　optimized　substrate　temperature　was　found　to　be　700　degrees　C　at　which　the　STO　films＇　structure　could　uniformly　dense.　The　STO　films　present　a　low　optical　absorption　in　the　400　similar　to　1000nm　wavelength　range,　and　the　substrate　temperature　is　not　the　main　reason　for　the　impact　of　the　optical　absorption.　The　optical　band　gap　energy　was　found　to　be　about　3.5　similar　to　4.0eV　for　the　STO　thin　film.　The　valences　of　the　three　elements　(Sr,　Ti,　and　O)　in　the　STO　film　prepared　by　PLD　are　2+,　4+　and　2-,　respectively.