As　a　popular　controllable-released　carrier,　intelligent　hydrogels　are　often　used　in　drug　delivery　and　disease　therapeutics.　Meanwhile,　benefit　from　the　mimic-enzyme　activity　performance,　Fe–N–C　nanozymes　have　been　widely　used　in　sensing　and　analysis.　However,　the　combination　of　intelligent　hydrogels　with　specific　degradability　and　Fe–N–C　nanozymes　with　enhanced　activity　in　one　system　to　achieve　controllable　and　sensitive　detection　is　rare.　Herein,　we　combine　intelligent　hydrogel　with　mimic　peroxidase　activity　enhanced　Fe–N–C　nanozymes　to　construct　a　ratiometric　fluorescence　probe　for　sensitive　detection　of　hyaluronidase　(HAase).　The　modification　of　copper　ions　has　been　proved　to　enhance　the　mimic　enzyme　activity　of　Fe–N–C　nanozymes　greatly.　Cu2+　modified　Fe–N–C　nanozymes　were　embedded　in　hyaluronic　acid　hydrogel.　In　the　presence　of　HAase,　the　HA　hydrogel　structure　was　hydrolyzed　and　released　Cu2+-Fe-N-C　nanozymes　gradually.　The　released　Cu2+-Fe-N-C　nanozymes　are　used　to　catalyze　the　hydrogen　peroxide　system　so　that　o-phenylenediamine　is　oxidized　to　orange　fluorescent　2,　3-diaminophenolazine　(DAP).　Due　to　the　electrostatic　interaction,　the　fluorescence　resonance　energy　transfer　can　occur　between　the　negatively　charged　copper　nanoclusters　emitted　by　430　nm　and　the　positively　charged　DAP　emitted　by　560　nm.　The　activity　of　HAase　was　monitored　according　to　the　ratio　of　fluorescence　intensity　at　560　nm　and　430　nm　(F560/F430).　The　linear　range　of　this　method　is　0–10.0　U/ml　and　the　detection　limit　is　0.43　U/mL　(S/N　=　3).　This　strategy　has　been　further　applied　to　biological　samples　successfully.　©　2021