TiO2　bilayer　films　with　a　normal　surface　(Ns-TiO2),　surface　defects　(Sd-TiO2),　and　interface　defects　(Id-TiO2)　were　successfully　prepared　by　a　combination　of　cold　plasma　treatment　(CPT)　and　sol-gel　dip-coating　technology.　The　photodegradation　of　rhodamine　B　(RhB)　over　these　as-prepared　TiO2　films　was　investigated　via　UV-vis　irradiation.　Results　indicate　that　the　three　kinds　of　films　exhibit　very　different　photodegradation　processes　for　RhB.　A　mainly　N-deethylation　reaction　over　the　Ns-TiO2　films,　whereas　an　efficient　degradation　(cycloreversion)　of　RhB　occurs　over　the　Sd-TiO2　films.　In　the　RhB/Id-TiO2　system,　however,　efficient　N-deethylation　concomitant　with　the　highly　efficient　cycloreversion　of　RhB　is　observed.　The　efficiency　of　the　complete　mineralization　of　RhB　dye　follows　the　order　of　Id-TiO2＞Sd-TiO　2＞Ns-TiO2.　It　is　proposed　that　the　defect　sites　at　the　surface　or　the　interface　of　TiO2　films　promote　the　separation　of　photogenerated　electron-holes,　leading　to　a　higher　photoactivity　of　defective　TiO2　films.　Moreover,　the　higher　stability　over　Id-TiO2　as　compared　to　Sd-TiO2　indicates　that　the　interface　defect　sites　in　TiO2　could　be　applied　in　environmental　photocatalysis.　©　2010　American　Chemical　Society.