Semiconductor　quantum　dots　(QDs)　have　attracted　extensive　attention　because　of　their　remarkable　optical　and　electrical　characteristics.　However,　the　practical　application　of　QDs　and　further　the　QD　composite　films　have　greatly　been　hindered　mainly　owing　to　their　essential　drawbacks　of　extreme　unstability　under　oxygen　and　water　environments.　Herein,　one　simple　method　has　been　employed　to　enhance　enormously　the　stability　of　CdxZn1-xSeyS1-y　QD　composite　films　by　a　combination　of　CdxZn1-xSeyS1-y　QDs　and　poly(vinylidene)　fluoride　(PVDF),　which　is　characteristic　of　closely　arranged　molecular　chains　and　strong　hydrogen　bonds.　There　are　many　particular　advantages　in　using　QD/PVDF　composite　films　such　as　easy　processing,　low　cost,　large-area　fabrication,　and　especially　extreme　stability　even　in　the　boiling　water　for　more　than　240　min.　By　employing　K2SiF6:Mn4+　as　a　red　phosphor,　a　prototype　white　light-emitting　diode　(WLED)　with　color　coordinates　of　(0.3307,　0.3387),　T-c　of　5568　K,　and　color　gamut　112.1NTSC(1931)%　at　20　mA　has　been　fabricated,　and　there　is　little　variation　under　different　excitation　currents,　indicating　that　the　QD/PVDF　composite　films　fabricated　by　this　simple　blade-coating　process　make　them　ideal　candidates　for　liquid-crystal　display　backlight　utilization　via　assembling　a　WLED　on　a　large　scale　owing　to　its　ultrahigh　stability　under　severe　environments.