CdSe-based　quantum　dots　(QDs)　have　increasingly　become　important　QDs　for　emerging　display　material　because　of　their　suitable　bandgap,　controllable　size,　and　high　PLQY.　However,　there　are　still　many　problems　with　CdSe　QD　films,　including　severe　fluorescence　quenching　and　low　conductivity.　Herein,　we　replace　the　long　insulated　oleic　acid　ligand　with　the　shorter　thiol　ligand　to　enhance　the　mobility　of　charge　carriers.　It　was　found　that　the　QDs　with　octanethiol　in　a　quantum　dot　light-emitting　diode　(QLED)　exhibited　higher　conductivity　and　lower　turn-on　voltage.　Moreover,　the　defects　on　the　surface　of　the　QD　layer　were　effectively　passivated　by　adding　a　thin　layer　of　cesium　carbonate,　and　the　radiation　recombination　of　the　quantum　dot　light-emitting　layer　was　also　significantly　improved.　It　was　evident　that　the　performance　of　the　optimized　QLED　device　was　improved　with　a　peak　luminance　of　166　300-294　500　cd/m(2)　and　a　peak　current　efficiency　of　10-32　cd/A.　Thus,　the　current　work　provides　two　ways　to　optimize　QD　films　and　proposes　a　method　to　improve　the　performance　of　QLEDs.