The　development　of　quantum　dot　(QD)　composite　films　for　lighting　and　displays　is　of　great　importance　because　of　their　exceptional　mechanical　flexibility,　chemical　stability,　and　optical　tunability.　Generally,　QDs　are　attached　to　plasmonic　nanostructures　to　enhance　their　photoluminescence　(PL)　emission.　However,　plasmonic　QD　composite　films　suffer　from　deteriorated　inherent　quantum　yields　and　lower　enhancement　ratios　due　to　variations　in　the　refractive　index　and　dielectricity　in　the　composites.　Herein,　the　use　of　a　dielectric　microsphere　cavity　is　reported　to　realize　over　1000-fold　enhancement　of　the　PL　in　CdSe/ZnS　QD/polydimethylsiloxane　films　with　a　highly　unidirectional　emission　angle　of　approximate　to　9　degrees.　The　field　regulation　by　the　optical　whispering-gallery　resonance　and　directional　antenna　effect　at　the　microscale　is　revealed　to　interpret　the　PL　enhancement　mechanism.　Additionally,　the　microsphere　cavity　allows　for　the　enhancement　of　white-light　emission　in　the　RGB-QD　hybrid　composite　film.　The　present　work　inspires　a　straightforward　strategy　for　boosting　the　light　efficiency　in　QD　composite　films,　with　promising　applications　in　flexible　lighting/display　devices.