In　this　work,　cadmium　nitrate　hexahydrate　[Cd(NO3)2·6H2O]　is　as　a　source　of　cadmium,　zinc　nitrate　[Zn(NO3)2]　as　a　source　of　zinc　source,　and　NaHSe　as　a　source　of　selenium　which　was　prepared　through　reducing　the　elemental　selenium　with　sodium　borohydride　(NaBH4).　Then　water-soluble　Cd1-xZnxSe　ternary　quantum　dots　with　different　component　were　prepared　by　colloid　chemistry.　The　as-prepared　Cd1-xZnxSe　ternary　quantum　dots　exhibit　stable　fluorescent　property　in　aqueous　solution,　and　can　still　maintain　good　dispersivity　at　room　temperature　for　four　months.　Powder　X-ray　diffraction　(XRD)　and　high　resolution　transmission　electron　microscope　(HRTEM)　were　used　to　analyze　crystal　structure　and　morphology　of　the　prepared　Cd1-xZnxSe.　It　is　found　that　the　as-prepared　ternary　quantum　dots　are　cubic　phase,　show　as　sphere,　and　the　average　of　particle　size　is　approximate　4　nm.　The　spectral　properties　and　energy　band　structure　of　the　as-prepared　ternary　quantum　dots　were　modulated　through　changing　the　atom　ratio　of　elements　Zn　and　Cd.　Compared　with　binary　quantum　dots　CdSe　and　ZnSe,　the　ultraviolet-visible　(UV-Visible)　absorption　spectrum　and　fluorescence　(FL)　emission　spectrum　of　ternary　quantum　dots　are　both　red-shift.　The　composites　(Cd0.5Zn0.5Se@TNTs)　of　Cd0.5Zn0.5Se　ternary　quantum　dots　and　TiO2　nanotubes　(TNTs)　were　prepared　by　directly　immerging　TNTs　into　quantum　dots　dispersive　solution　for　5　hours.　TEM　image　shows　that　the　Cd0.5Zn0.5Se　ternary　quantum　dots　were　closely　combined　to　nanotube　surface.　The　infrared　spectra　show　that　the　Ti-Se　bond　was　formed　between　Cd0.5Zn0.5Se　ternary　quantum　dots　and　TiO2　nanotubes,　which　improve　the　stability　of　the　composite.　Compared　to　pristine　TNTs,　UV-Visible　absorption　spectrum　of　the　composites　is　significantly　enhanced　in　the　visible　region　of　light.　And　the　absorption　band　edge　of　Cd0.5Zn0.5Se@TNTs　red-shift　from　400　to　700　nm.　The　recombination　of　the　photogenerated　electron-hole　pairs　was　restrained　with　the　as-prepared　ternary　quantum　dots.　Therefore,　the　visible-light　photocatalytic　efficiency　was　greatly　improved.　After　visible-light　irradiation　for　60　min,　the　degradation　of　Cd0.5Zn0.5Se@TNTs　photocatalysts　for　RhB　is　nearly　100%,　which　is　about　3.3　times　of　that　of　pristine　TNTs　and　2.5　times　of　that　of　pure　Cd0.5Zn0.5Se　ternary　quantum　dots,　respectively.　©　2015,　Science　Press.　All　right　reserved.