In　this　paper,　Cs2NaErCl6　double　perovskites　microcrystals　(MCs)　co-doped　with　Yb3+　and　Bi3+　are　successfully　synthesized　by　a　simple　＇dissolving-drying＇　method.　When　excited　at　379　nm,　808　nm　and　980　nm,　the　MCs　show　strong　red,　green　and　yellow　light,　respectively,　which　can　be　well　distinguished　by　the　naked　eyes.　On　this　basis,　two　kinds　of　systems　are　designed　with　doped/undoped　MCs　for　triple-mode　fluorescent　anti-counterfeiting　and　information　encryption　of　numbers　and　characters.　The　results　indicate　that　our　MCs　are　not　only　beneficial　to　the　application　of　fluorescent　anti-counterfeiting,　but　also　greatly　improve　the　security　of　anti-counterfeiting.　In　addition,　we　evaluate　the　temperature　sensing　performance　of　these　MCs　by　fluorescence　intensity　ratio　technique.　The　samples　show　a　high　relative　sensitivity　as　3.8　%/K　at　243　K.　The　results　show　that　the　samples　have　multi-functional　applications　in　the　fields　of　fluorescent　anti-counterfeiting　and　temperature　sensing,　and　this　work　will　broaden　the　application　fields　of　lead-free　double　perovskites　in　fluorescent　anti-counterfeiting　and　temperature　sensing.　©　2024　Elsevier　B.V.