Perovskite　quantum　dots　are　considered　an　ideal　alternative　to　traditional　phosphor　color　converters　because　of　their　excellent　optical　properties.　However,　the　bottleneck　problem　of　instability　has　tremendously　limited　their　practical　applications.　In　the　present　work,　we　fabricate　green-emitting　CsPbBr3@glass　and　red-emitting　CsPbBr1.5I1.5@glass　nanocomposites　via　an　in-situ　nucleation/growth　method.　Importantly,　the　CsPbX3@glass　(X-3　=　Br-3,　Br1.5I1.5)　samples　exhibit　striking　thermal　reversibility　in　the　heating/cooling　cycle　experiments.　Furthermore,　CsPbX3　monolithic　films　with　high　photoluminescence　quantum　yields　(PLQYs)　of　80-95%　and　narrow　full-width　at　half-maximum　(FWHM)　down　to　16　nm　are　achieved　by　dispersing　ground　CsPbX3@glass　particles　in　polydimethylsiloxane　(PDMS)　matrix.　Benefiting　from　dual　encapsulation　of　inorganic　glass　matrix　and　organic　polymer　matrix,　the　film　can　endure　harsh　accelerated　aging　tests　(at　85　degrees　C/85%RH　for　500　h).　Finally,　combining　the　as-prepared　yellow　monolithic　film　with　blue　chips　as　the　backlight　endows　the　liquid　crystal　display　(LCD)　with　a　wide　color　gamut　(a　color　gamut　of　146%　of　commercial　LCD,　101%　of　NTSC　after　passing　the　color　filters),　demonstrating　great　prospects　in　the　display　industry.