CuAlO2　films　with　different　thickness　were　prepared　by　the　radio　frequency　magnetron　sputtering　technique.　The　structural,　electrical　and　optical　properties　of　CuAlO2　were　studied　by　X-ray　diffraction,　atomic　force　microscope,　UV-Vis　double-beam　spectrophotometer　and　Hall　measurements.　The　results　indicate　that　the　single　phase　hexagonal　CuAlO2　is　formed　and　the　average　grain　size　of　CuAlO2　films　increases　with　increasing　film　thickness.　The　results　also　exhibit　that　the　lowering　of　bandgap　and　the　increase　of　electrical　conductivity　of　CuAlO2　films　with　the　increase　of　their　thickness,　which　are　attributed　to　the　improvement　of　the　grain　size　and　the　anisotropic　electrical　property.　According　to　the　electrical　and　optical　properties,　the　biggest　figure　of　merit　is　achieved　for　the　CuAlO2　film　with　the　appropriate　thickness　of　165　nm.　(C)　2014　Elsevier　Ltd.　All　rights　reserved.