Nanocrystalline　-In2S3　was　prepared　by　reacting　In(NO3)(3)　with　thioacetamide　through　hydrothermal　method　at　120　degrees　C　for　12h.　The　size　and　morphology　of　In2S3　photocatalyst　were　characterized　using　X-ray　diffraction　(XRD),　scanning　electron　microscope　(SEM),　transmission　electron　microscopy　(TEM),　and　Brunauer-Emmett-Teller　(BET)　surface　area　analysis.　The　band　gap　energy　was　measured　using　Kulbeka-Munk　function　and　the　electronic　state　of　the　prepared　In2S3　was　determined　by　X-ray　photoelectron　spectroscopy.　The　photocatalytic　activity　of　the　prepared　sample　was　investigated　by　the　photocatalytic　degradation　with　20mg/L　of　the　tetracycline　(TC)　under　natural　sunlight　as　a　source　of　irradiation.　The　results　showed　that　the　synthesized　In2S3　matches　completely　with　the　cubic　phase　of　-In2S3　with　a　surface　area　of　95.6726m(2)g(-1),　and　the　photocatalytic　activity　for　the　degradation　of　TC　under　natural　sunlight　irradiation　was　excellent　followed　with　first-order　kinetics　and　the　complete　removal　could　be　within　30min,　which　suggests　that　the　prepared　photocatalyst　has　the　potential　to　degrade　the　antibiotics.