CZTS　thin　films　have　been　prepared　from　the　electrolyte　with　different　pH　values　by　co-electrodeposition.　The　effects　of　bath　pH　value　on　the　cyclic　voltammetry,　structure,　morphology,　composition　and　optical　properties　of　CZTS　thin　films　have　been　investigated　in　details.　Cyclic　voltammetry　measurements　reveal　that　pH　value　impacts　the　reduction　potential　of　metals　and　the　composition　in　precursors.　The　analyses　of　XRD　and　Raman　spectroscopy　suggest　that　the　CZTS　films　have　better　crystallinity　and　less　secondary　phases　when　the　bath　pH　is　about　5.0.　The　chemical　composition　and　morphological　studies　indicate　the　formation　of　compact　and　homogenous　CZTS　thin　films　with　stoichiometric　composition　at　a　pH　value　of　5.0.　And　its　bandgap　energy　is　around　1.49　eV.　(C)　2016　The　Electrochemical　Society.　All　rights　reserved.