Effective　utilization　of　solar　energy　through　photocatalytic　oxidation　is　of　great　significance　for　environmental　restoration　and　sustainable　development.　In　order　to　realize　the　rapid　separation　of　electron-hole　pairs　and　improve　the　photocatalytic　degradation　activity,　a　multifunctional　CsPbBr3/BiOI/TiO2　nanofiber　photocatalyst　with　a　symmetric　double　heterojunction　structure　is　synthesized　by　combining　electrospinning,　hydrothermal　and　wet　impregnation　methods.　Compared　with　powder　photocatalysts,　polyacrylonitrile　(PAN)　composite　fibers　work　as　a　carrier　offering　the　advantages　of　reusability,　excellent　flexibility,　thermal　stability,　a　controlled　structure　and　a　large　specific　surface　area.　Benefiting　from　the　effective　interfacial　charge　transfer　and　enhanced　visible-light　absorption,　the　obtained　CsPbBr3/BiOI/TiO2@PAN　nanofibers　exhibit　superior　photocatalytic　efficiency　for　rhodamine　B,　tetracycline　hydrochloride,　phenol　and　bisphenol　A　under　simulated　sun-light　irradiation.　Based　on　fluorescence　intensity　ratio　(FIR)　thermometry,　the　emission　peaks　of　CsPbBr3　at　516　nm　and　PAN　at　479　nm　can　be　utilized　for　accurate　non-contact　temperature　monitoring　and　real-time　thermal　feedback　in　complex　degradation　systems,　and　the　maximum　relative　sensitivity　S-R　is　obtained　as　0.0117　K-1　at　353　K.　In　conclusion,　multi-selective　photocatalysis　fibers　with　real-time　optical　thermometry　properties　provide　new　application　prospects　for　water　purification　in　extremely　harsh　environments.