Surface　plasmon　effects　of　Ag　nanoparticles　(NPs)　have　been　extensively　applied　to　enhance　upconversion　luminescence　(UCL)　properties　of　the　nanoparticles　doped　with　rare　earth　ions.　However,　it　is　important　to　control　the　effective　coupling　distance　between　the　Ag　NPs　and　the　upconversion　nanoparticles　(UCNPs).　In　this　work,　the　Ag/ZnO/UC　composite　films　were　fabricated　by　vacuum　methods,　and　the　influence　of　the　ZnO　spacer　layer　thickness　on　spectral　properties　was　investigated.　These　studies　reveal　that　the　ZnO　spacer　thickness　has　a　strong　effect　on　the　Ag　NPs　plasma　resonance　and　UCL　intensity.　The　highest　enhancement　factors　of　the　red　and　green　emissions　were　found　to　be　18.6　and　5.3　under　980 nm　excitation,　respectively.　That　is　attributed　to　the　enhancement　of　the　absorption　and　excitation　rate　for　UCNPs　under　the　equilibrium　between　non-radiative　energy　and　local　field　effect.　©　2021,　The　Author(s),　under　exclusive　licence　to　Springer-Verlag　GmbH,　DE　part　of　Springer　Nature.