Oxidative　stress,　orchestrated　by　myeloperoxidase　(MPO),　plays　crucial　roles in　the　progression　of　many　diseases.　Nonetheless,　the　role　of　MPO-mediated　oxidative　stress　in　distinct　factor-induced　acute　liver　injuries　(ALI)　is　still　up　for　dispute,　mainly　due　to　the　lack　of　probes　for　in　vivo　monitoring　of　MPO　releases.　Here,　a　highly　selective　MPO　probe　(CSQ)　based　on　the　epoxidation　biochemical　reaction　within　the　MPO-H2O2-Cl−　system　is　screened　to　construct　dual　near　infrared-IIb　(NIR-IIb) ratiometric　(F1550Em,　808Ex/F1550Em,　980Ex)　luminescence　nanoprobes　by　integrating　CSQ　onto　down　conversion　nanoparticles　(DCNPs)　with　and　without　liver-targeting　moiety　(twin　NIR-IIb　nanoprobes).　Liver-targeting　probes　are　employed　to　monitor　MPO　release,　whereas　non-liver-targeting　probes　are　utilized　to　assess　MPO　activity　across　all　cell　types.　Using　twin　NIR-IIb　nanoprobes,　the　MPO-mediated　oxidative　stress　progressively　increased　are　observed　in　carbon　tetrachloride　(CCl4)-induced　ALI　over　12 h.　In　contrast,　the　MPO-mediated　oxidative　stress　in　acetaminophen　(APAP)-induced　ALI　initially　increased,　peaked　within　3 h,　and　then　rapidly　weakened　to　normal　levels　within　12 h.　Importantly,　the　differential　release　of　MPO　from　neutrophils/Kupfer　cells　to　extracellular　fluids　in　the　two　types　of　ALI　is　revealed.　This　work　reveals　significant　differences　in　MPO　distribution　and　the　role　of　MPO-mediated　oxidative　stress　in　CCl4　and　APAP-induced　ALI.　©　2024　Wiley-VCH　GmbH.