Tin　monosulfide　(SnS)　and　indium　thin　films　were　successively　deposited　onto　glass　substrates　by　thermal　evaporation　(with　indium　proportion　of　0　at.%　to　12.49　at.%).　Then　the　films　were　annealed　in　vacuum　at　300°C　for　2h　in　order　to　obtain　different　In-doped　concentration　SnS　(SnS:　In)　films.　The　structural,　electrical　and　optical　properties　of　the　SnS:　In　thin　films　were　characterized　using　X-ray　diffraction　(XRD),　scanning　electron　microscope　(SEM),　Hall　Effect　Measurement　System　and　UV/VIS/NIR　Spectrometer.　The　result　shows　that　the　films　are　polycrystalline　SnS　with　orthogonal　structure,　and　the　crystallites　in　the　films　are　exclusively　oriented　along　(111)　direction.　All　the　films　are　of　p-type　conductivity.　With　the　indium　proportion　increased　from　0　at%　to　12.49　at%,　the　optical　bandgaps　of　the　films　are　decreased　from　1.37eV　to　1.12eV,　and　the　carrier　concentration　of　the　films　is　increased　observably,　whereas　their　resistivity　and　carrier　mobility　are　decreased　straightly　In-doping　with　a　certain　quantity　can　improve　the　semiconducting　properties　of　the　films　and　it　is　possible　to　produce　suitable　SnS:　In　thin　films　as　absorbers　in　thin　film　solar　cells.　©　The　Electrochemical　Society.