All-inorganic　perovskite　quantum　dots　have　attracted　much　attention　because　of　their　outstanding　photoelectric　properties.　However　the　instability　of　PQDs　to　the　environment　has　become　a　potential　threat　that　restricts　its　practical　application.　At　present　a　large　number　of　scientific　studies　have　been　devoted　to　improving　the　stability　of　PQDs.　However　most　of　the　current　stability　improvement　schemes　are　to　encapsulate　PQDs　in　hydrophobic　materials　to　provide　a　physical　barrier　against　environmental　changes　while　the　defects　and　unstable　performance　of　materials　themselves　have　not　been　effectively　improved.　It　is　therefore　of　great　significance　to　study　the　corresponding　performance　and　stability　improvement　schemes　from　the　PQDs　material　itself.Ion　exchange　resin　is　a　kind　of　polymer　compound　with　a　functional　group　a　network　structure　and　insolubility.　As　for　anion　exchange　resin　its　active　group　can　adsorb　different　types　of　anions　to　achieve　ion　exchange　reaction　while　PQDs　is　a　kind　of　ionic　compound　containing　halogen　anions　and　the　two　have　a　good　binding　ability.　In　this　study　the　performance　and　stability　of　CsPbBr3　PQDs　were　improved　simultaneously　by　introducing　defect　passivation　and　selective　removal　of　ion　exchange　resin.　The　product　PQDs　prepared　by　high　temperature　thermal　injection　method　was　named　as　the　original　sample　and　the　sample　treated　with　Br　type　anion　exchange　resin　was　named　as　the　modified　sample.　From　direct　observation　of　their　appearance　the　original　sample　is　yellow-brown　while　the　modified　sample　after　ion　exchange　resin　treatment　is　transparent　green.　The　resean　is　the　large　number　of　micropores　in　the　ion　exchange　resin　which　has　strong　an　adsorption　capacity　comparable　to　activated　carbon　and　can　selectively　adsorb　and　remove　organic　impurities.　TEM　images　show　that　the　original　sample　has　poor　surface　morphology.　In　contrast　the　modified　samples　treated　with　ion-exchange　resin　show　clear　cubic　phase　with　almost　no　surface　damage　or　structural　distortion.　It　is　worth　mentioning　that　continuous　UV　excitation　and　high　temperature　environment　will　lead　to　partial　crystal　phase　separation　of　PQDs　and　the　surface　ligand　will　fall　off　resulting　in　grain　agglomeration　and　decreased　fluorescence　intensity.　The　luminescence　intensity　of　the　original　sample　and　the　modified　sample　decreases　to　80.6%　and　85.7%　respectively　after　3　h　of　UV　excitation　and　to　75.2%　and　99.6%　respectively　after　2　hours　of　70　heating.　Obviously　the　fluorescence　intensity　attenuation　of　the　modified　sample　is　relatively　less　showing　more　excellent　stability.　It　is　worth　noting　that　after　high　temperature　heating　the　fluorescence　intensity　of　the　modified　sample　almost　does　not　decay　showing　excellent　thermal　stability.　Compared　with　the　original　sample　the　modified　sample　also　had　a　longer　average　fluorescence　lifetime.　The　third-order　exponential　decay　model　was　used　to　fit　the　fluorescence　lifetime　curve　and　the　results　show　that　the　average　fluorescence　lifetime　of　the　original　sample　and　the　modified　sample　was　10.4　ns　and　22.2　ns　respectively.　The　defects　in　the　crystal　will　act　as　the　center　of　non-radiation　recombination　to　inhibit　the　radiation　recombination　process　and　the　increase　of　the　final　average　fluorescence　life　indicates　that　the　radiation　recombination　is　enhanced　which　also　reflects　the　reduction　of　defect　states　from　the　side.　The　improvement　of　average　fluorescence　lifetime　indicates　that　the　excess　halogen　anions　released　by　anion　exchange　resin　contribute　largely　to　the　passivation　of　surface　defects　and　the　improvement　of　optical　properties　of　PQDs.　The　PLQY　of　the　original　sample　and　the　modified　sample　were　53.23%　and　90.00%　respectively.　Such　a　large　increase　in　PLQY　is　not　only　due　to　the　direct　band　gap　characteristics　of　the　material　itself　which　can　improve　the　light　absorption　coefficient　and　speed　up　the　radiation　recombination　rate　but　also　due　to　the　passivation　of　excessive　halogen　anions　on　the　surface　defects　of　quantum　dots　thus　reducing　a　large　number　of　non-radiation　recombination　paths.In　summary　the　introduction　of　ion　exchange　resin　can　selectively　remove　PQDs　single　crystals　with　poor　morphology　and　unstable　structure　without　changing　the　inherent　crystal　phase　of　PQDs　which　makes　the　surface　morphology　and　uniformity　of　the　prepared　PQDs　greatly　improved.　And　the　stability　of　PQDs　has　also　been　greatly　improved　under　long-term　ultraviolet　light　and　high　temperature　experiments.　Moreover　before　and　after　modification　the　photoluminescence　quantum　yield　and　fluorescence　lifetime　of　CsPbBr3　PQDs　were　significantly　increased　from　53.23%　to　90.00%　and　from　10.4　ns　to　22.2　ns　respectively.　This　research　provides　a　new　idea　for　improving　the　performance　and　stability　of　PQDs.　Due　to　the　reproducible　and　low-cost　characteristics　of　ion　exchange　resins　it　has　broad　application　prospects　in　the　field　of　optoelectronics.　©　2022　Chinese　Optical　Society.　All　rights　reserved.