A　typical　hydrothermal　synthesis　was　employed　to　prepare　titania　nanotubes　(TNTs)　with　anatase　crystal　structure　using　P25　as　a　raw　material.　The　effects　of　hydrothermal　reaction　temperature,　calcination　temperature　on　the　morphology　and　crystal　structure　of　TNTs　were　investigated.　CdS　quantum　dots　(QDs)　formed　in　situ　were　assembled　onto　the　surfaces　of　TNTs　to　form　CdS/TNTs　nanocomposite　photocatalyst　by　using　bifunctional　organic　linker,　thiolactic　acid.　The　effects　of　thiolactic　acid　concentration　on　the　loading　amount　of　CdS　QDs　and　photoactivity　of　CdS/TNTs　nanocomposite　were　also　studied.　The　results　indicated　that　when　the　hydrothermal　reaction　and　calcination　temperatures　were　150　and　400°C,　respectively,　TNTs　have　anatase　crystal　structure　with　following　unique　properties,　an　average　diameter　of　about　8-10　nm,　the　length　of　several　hundred　nanometers　with　uniform　inner　and　outer　diameter　along　the　length　direction,　tube　wall　with　multilayer　structure　of　about　2-3　nm.　After　modification　with　CdS　QDs,　the　absorption　of　CdS/TNTs　nanocomposite　in　visible　light　area　was　enhanced　greatly,　compared　with　that　of　TNTs.　The　absorption　edge　of　CdS/TNTs　was　extended　to　580　nm.　The　CdS/TNTs　exhibited　excellent　photocatalytic　performance　for　RhB　degradation　under　visible　light　irradiation　simulated　by　halogen　tungsten　lamp.