Hydrogen　sulfide　(H2S),　as　a　hazardous　gas,　is　often　found　around　dump　areas.　Long　term　exposure　can　cause　harm　to　health,　it　is　highly　necessary　to　develop　some　simple　and　sensitive　methods　for　on-site　H2S　detection.　Herein,　a　convenient　photothermal　assay　has　been　designed　for　the　quantitation　of　H2S　using　a　handheld　thermometer　as　readout.　Au@Ag　nanocubes　(Au@Ag　NCs),　a　core-shell　nanocomposite　with　strong　light　absorption　at　similar　to　450　nm,　was　chosen　as　a　novel　photothermal　agent　in　this　study.　Under　the　laser　irradiation　at　450　nm,　the　Au@Ag　NCs　show　a　strong　photothermal　effect,　and　a　significant　temperature　enhancement　can　be　measured　by　the　thermometer　easily.　The　presence　of　H2S　can　lead　to　the　deposition　of　sulfur　onto　Au@Ag　NCs,　altering　the　localized　surface　plasmon　resonance　absorption,　size,　surface　composition,　and　morphology　of　Au@Ag　NCs　and　hence　leading　to　the　reduction　of　photothermal　effect.　The　change　of　the　temperature　has　a　linear　relationship　with　the　H2S　concentration　in　the　range　of　0.5-80.0　mu　M　with　a　detection　limit　of　0.35　mu　M.　By　combining　with　simple　sample　purification　procedures,　the　developed　method　has　been　applied　to　detect　H2S　in　garbage　odor　gas　with　satisfactory　results.　(C)　2021　Elsevier　B.V.　All　rights　reserved.