Cu2O/TiO2　nano-nano　heterostructures　with　different　concentrations　of　Cu2O　were　prepared　by　an　alcohol-aqueous　based　chemical　precipitation　method,　and　were　characterized　by　X-ray　diffraction,　transmission　electron　microscopy,　scanning　electron　microscopy　and　UV-vis　diffuse　reflection　absorption　spectra.　The　photocatalytic　efficiency　of　the　Cu2O/TiO2　heterostructures　was　evaluated　by　degradation　of　Acid　Orange　11　in　water　under　UV-vis　light　and　visible　light　irradiation.　The　results　show　that　the　heterostructures　have　dramatically　improved　photocatalytic　activity　comparing　with　pure　TiO2　(P25).　The　prepared　Cu2O/TiO2　heterostructures　with　the　Cu2O　concentrations　of　30%　and　70%　have　the　best　photocatalytic　efficiencies,　which　are　6　times　and　27　times　higher　than　that　of　pure　TiO2　(P25)　under　UV-vis　light　and　visible　light　irradiation,　respectively.　(c)　2009　Elsevier　B.V.　All　rights　reserved.