The　entry　of　Hg2+　into　the　human　body　can　lead　to　serious　damage　to　some　organs　and　it　is　vital　to　construct　some　simple　but　sensitive　Hg2+　assay　methods.　A　multicolor　sensor　for　Hg2+　was　constructed　depended　on　the　inhibition　of　peroxidase　activity　of　Fe/Co-MIL-88(NH2)　mediated　by　DNA　and　color　change　caused　by　the　etching　of　gold　nanobipyramids　(Au　NBPs).　The　enzymatic　activity　of　Fe/Co-MIL-88(NH2)　can　be　inhibited　by　adsorbing　the　T-rich　oligonucleotide　sequence　on　its　surface.　Hg2+　can　combine　with　thymine　of　the　T-rich　oligonucleotide　sequence　to　constitute　T-Hg2+-T　complex,　and　cause　the　transforming　of　T-rich　oligonucleotide　sequence　into　three-dimensional　structure　and　desorbed　from　Fe/Co-MIL-88(NH2)　surface.　Which　results　in　the　restoration　of　the　peroxidase　activity　of　Fe/Co-MIL-88(NH2),　and　then　it　catalyzes　the　3,3′,5,5′-tetramethylbenzidine　(TMB)　to　engender　TMB2+,　TMB2+　can　etch　Au　NBPs,　this　accompanied　with　a　peak　shift　of　the　UV–vis　spectrum　and　recognizable　color　changes　of　the　system.　Semi-quantitative　can　be　realized　using　the　multicolor　changes　of　the　Au　NBPs　as　the　reading　mode.　Furthermore,　quantitative　sensing　can　be　achieved　by　measuring　the　UV–vis　peak　shift　of　the　system.　The　linear　response　range　is　1.0　nM–10　µM,　and　the　detection　limit　(LOD)　is　0.28　nM.　©　2023　Elsevier　B.V.