Nb-doped　beta-Ga2O3　films　were　deposited　on　p-Si　(100)　and　quartz　substrates　using　radio　frequency　magnetron　sputtering　technology　at　various　substrate　temperatures.　All　the　films　annealed　in　an　argon　ambient.　The　surface　morphology　and　crystal　structure　of　the　films　were　studied　using　atomic　force　microscope　and　x-ray　diffraction　technologies,　and　the　results　indicated　that　the　film　had　a　flat　surface　and　a　good　crystal　structure　when　the　substrate　temperature　was　523　K.　We　investigated　the　optical　properties　of　the　samples,　and　the　results　highlight　that　Nb-doped　beta-Ga2O3　films　exhibit　high　transmittance　of　above　80%　to　UV-visible　light　with　a　wavelength　above　400　nm.　Furthermore,　the　optical　band　gap　of　the　Nb-doped　beta-Ga2O3　films　decreases　with　increasing　substrate　temperature.　The　electrical　characteristics　show　that　the　current　is　larger,　and　that　the　contact　between　the　Ag　electrode　and　the　Nb-doped　beta-Ga2O3　film　is　an　ohmic　contact,　when　the　substrate　temperature　is　523　K.　All　the　results　are　beneficial　for　practical　applications.