We　have　demonstrated　an　improved　quantum　dot　(QD)　and　silica　hybrid　nanocomposite　by　interfacial　optimization　for　simultaneous　enhancement　of　fluorescence　retention　and　stability.　This　nanocomposite　was　synthesized　by　using　silica　spheres　as　cores,　adsorbing　gradient　alloy　QDs　(GA-QDs)　as　the　first　shell,　and　then　coating　a　silica　layer　as　the　other　outmost　shell　(termed　SiO2-GA-QD-SiO2).　The　retaining　ratio　of　pristine　fluorescence　intensity　after　silica　coating　was　found　to　be　significantly　improved　by　the　QDs＇　shell　interfacial　optimization　due　to　the　suppression　of　surface　defects.　The　mechanism　of　the　QDs＇　surface　trap　states　capturing　the　excitons　before　and　after　silica　coating　was　analyzed　in　detail.　The　results　show　that　the　optimized　SiO2-GA-QD-SiO2　nanocomposite　provides　the　highest　resulting　fluorescence　intensity　of　70%,　which　is　62%　and　33%　higher　than　those　of　the　other　two　conventional　structures.　Photoluminescent　liquid　crystal　display　backlight　samples　were　prepared　with　this　hybrid　nanocomposite　to　show　the　robustness　against　high　temperature　and　humid　environment.　Even　when　immersed　in　water　and　heated　to　80　degrees　C,　the　backlight　samples　still　retained　85%　of　the　initial　fluorescence,　which　was　40%　higher　than　that　with　bare　GA-QDs.　High　fluorescence　and　long-term　stability　highlight　the　potential　of　using　this　nanocomposite　in　displays　or　lighting　applications.