A　ratiometric　fluorescence　probe　is　proposed　for　sensitive　and　visual　detection　of　tetracyclinee　(TC)　based　on　cascade　fluorescence　signal　amplification　induced　by　bovine　serum　albumin–stabilized　copper　nanoclusters　(BSA-CuNCs)　and　yttrium　ions　(Y3+).　TC　can　combine　with　Y3+　to　form　the　complex　(TC-Y3+)　to　enhance　the　fluorescence　of　TC　at　515 nm.　Then,　positively　charged　TC-Y3+　and　negatively　charged　BSA-CuNCs　was　bonded　together　by　electrostatic　interactions　to　achieve　the　fluorescence　resonance　energy　transfer　(FRET)　process.　With　the　increase　of　TC　concentration,　the　fluorescence　intensity　of　TC-Y3+　at　515 nm　(F515)　gradually　increased;　meanwhile,　the　fluorescence　intensity　of　BSA-CuNCs　at　405 nm　(F405)　decreased　gradually.　The　ratio　of　F515　and　F405　was　used　for　the　quantitative　determination　of　TC.　The　linear　range　of　the　constructed　fluorescent　probe　is　1.0　to　60.0 μM,　and　the　limit　of　detection　is　0.22 μM.　The　method　was　successfully　applied　to　the　determination　of　TC　in　spiked　milk　with　recoveries　ranging　from　94.3　to　112%.　Furthermore,　the　color　of　this　platform　can　be　observed　from　dark　violet　to　bright　green　under　the　UV　lamp.　Since　the　response　time　of　the　reaction　is　less　than　10 s,　an　intelligent　sensing　platform　based　on　the　use　of　the　smartphone　as　image　acquisition　equipment　was　also　established　to　realize　rapid　on-site　and　portable　detection　of　TC　through　the　colorimetric　recognition　application.　Graphical　abstract:　[Figure　not　available:　see　fulltext.]　©　2022,　The　Author(s),　under　exclusive　licence　to　Springer-Verlag　GmbH　Austria,　part　of　Springer　Nature.