In　this　paper,　ZnO　quantum　dots　(QDs)-CuO　nanowires　(NWs)　heterostructure　was　synthesized　by　a　mild　solution　method.　The　Al2O3　transition　layer　were　deposited　on　CuO　NWs　by　surface　modification　engineering　using　atomic　layer　deposition　(ALD)　to　increase　the　nucleation　probability　of　ZnO　QDs.　The　field　emission　properties　of　the　composites　were　investigated.　The　results　reveal　that　the　CuO@Al2O3/ZnO　QDs　ternary　heterostructures　have　the　turn-on　field　of　2.82　V/μm　and　the　field　emission　enhancement　factor　of　5798,　which　are　superior　to　that　of　ZnO　QDs-CuO　NWs　and　pure　CuO　NWs.　The　improvement　of　field　emission　performance　is　mainly　attributed　to　the　decrease　of　the　electron　transport　barrier　at　the　interface　and　the　increase　of　the　oxygen　vacancies,　making　it　easier　to　transport　electrons　to　ZnO　QDs.　The　use　of　amorphous　Al2O3　in　the　transition　layer　also　effectively　alleviates　the　lattice　mismatch　between　ZnO　QDs　and　the　substrate.　This　study　provides　an　effective　method　for　enhancing　the　field　emission　performance　of　the　core-shell　nanomaterial　device.　©　2020　Elsevier　Ltd　and　Techna　Group　S.r.l.