Metformin　is　commonly　used　for　clinical　treatment　of　type-2　diabetes,　but　long-term　or　overdose　intake　of　metformin　usually　causes　selective　upregulation　of　H2S　level　in　the　liver,　resulting　in　liver　injury.　Therefore,　tracking　the　changes　of　H2S　content　in　the　liver　would　contribute　to　the　prevention　and　diagnosis　of　liver　injury.　However,　in　the　literature,　there　are　few　reports　on　ratiometric　PA　molecular　probes　for　H2S　detection　in　drug-induced　liver　injury　(DILI).　Accordingly,　here　we　developed　a　H2S-activated　ratiometric　PA　probe,　namely　BDP-H2S,　based　Aza-BODIPY　dye　for　detecting　the　H2S　upregulation　of　metformin-induced　liver　injury.　Due　to　the　intramolecular　charge　transfer　(ICT)　effect,　BDP-H2S　exhibited　a　strong　PA　signal　at　770　nm.　Following　the　response　to　H2S,　its　ICT　effect　was　recovered　which　showed　a　decrement　of　PA770and　an　enhancement　of　PA840.　The　ratiometric　PA　signal　(PA840/PA770)　showed　excellent　H2S　selectivity　response　with　a　low　limit　of　detection　(0.59　μM).　Bioimaging　experiments　demonstrated　that　the　probe　has　been　successfully　used　for　ratiometric　PA　imaging　of　H2S　in　cells　and　metformin-induced　liver　injury　in　mice.　Overall,　the　designed　probe　emerges　as　a　powerful　tool　for　noninvasive　and　accurate　imaging　of　H2S　level　and　tracking　its　distribution　and　variation　in　liver　in-real　time.　©　2022　American　Chemical　Society.　All　rights　reserved.