The　development　of　a　simple　fluorescent　sensor　for　detecting　the　Pb2+　heavy　metal　is　fundamentally　important.　The　CH3NH3PbBr3　perovskite　material　exhibits　excellent　photoluminescence　properties　that　are　related　to　Pb2+.　Based　on　the　effects　of　Pb2+　on　the　luminescent　properties　of　CH3NH3PbBr3,　we　design　a　novel　platform　for　the　selective　fluorescence　detection　of　Pb2+　ions.　Herein,　we　use　a　CH3NH3Br　solution　at　a　high　concentration　as　the　fluorescent　probe.　Incorporation　of　PbBr2　into　the　CH3NH3Br　solution　results　in　a　rapid　chemical　reaction　to　form　CH3NH3PbBr3.　Hence,　the　nonfluorescent　CH3NH3Br　material　displays　a　sensitive　and　selective　luminescent　response　to　Pb2+　under　UV　light　illumination.　Moreover,　the　reaction　between　CH3NH3Br　and　PbBr2　could　transform　Pb2+　into　CH3NH3PbBr3,　and　therefore,　CH3NH3Br　may　also　be　used　to　extract　Pb2+　from　liquid　waste　in　recycling　applications.