SnS　films　were　prepared　onto　the　ITO-coated　glass　substrates　by　pulse-form　electro-deposition.　The　potential　applied　to　the　substrates　was　of　pulse-form　and　its　＂on＂　potential,　Von　was　-　0.75 V　(vs.　SCE　)and　＂off　＂　potential,　Voff　was　varied　in　the　range　of　-　0.1-0.5 V.　The　SnS　films　deposited　at　different　Voff　values　were　characterized　by　XRD,　EDX,　SEM　and　optical　measurements.　It　shows　that　all　the　films　are　polycrystalline　orthorhombic　SnS　with　grain　sizes　of　21.54-26.93 nm　and　lattice　dimensions　of　a　=　0.4426-0.4431 nm,　b　=　1.1124-1.1134 nm　and　c　=　0.3970-0.3973 nm,　though　the　Voff　has　some　influence　on　the　surface　morphology　of　the　films　and　Sn/S　ratio.　When　Voff　=　0.1-0.3 V,　the　SnS　films　have　the　best　uniformity,　density　and　adhesion,　and　the　Sn/S　ratio　is　close　to　1/1.　The　direct　band　gap　of　the　films　was　estimated　to　be　between　1.23　and　1.33 eV　with　standard　deviation　within　±　0.03 eV,　which　is　close　to　the　theoretical　value.　The　SnS　films　exhibit　p-type　or　n-type　conductivity　and　their　resistivity　was　measured　to　be　16.8-43.1 Ω　cm.　©　2006　Elsevier　B.V.　All　rights　reserved.