Great　achievements　about　lead-based　halide　perovskites　have　been　made　in　the　fields　of　photovoltaic　solar　cells,　light　emitting　diodes,　photodetectors,　and　thermoelectric　devices.　However,　the　toxicity　and　instability　of　lead-based　materials　hinder　their　practical　application.　Herein,　we　used　propane-1,3-diammonium　cation　to　construct　a　copper-based　halide　perovskite　material　(NH3C3H6NH3)CuBr4　with　a　two-dimensional　layered　structure.　This　material　exhibits　a　suitable　bandgap　of　1.71　eV　for　a　broad-band　absorption.　Dense　and　flexible　(NH3C3H6NH3)CuBr4　thin　film　can　be　obtained　by　simple　spin-coating　of　the　solution　using　green　solvent　DMSO.　Furthermore,　(NH3C3H6NH3)CuBr4　shows　excellent　stability　towards　temperature,　humidity　and　UV-light.　Finally,　the　(NH3C3H6NH3)CuBr4　thin　film　shows　a　reasonable　Seebeck　coefficient　of　-13.8　mu　V　K-1　and　a　power　factor　of　1.70　mu　W　m(-4)　K-2　at　298　K,　demonstrating　the　great　potential　for　flexible　n-type　thermoelectric　application.