High-sensibility detection method for trace metal ion

The invention related to a high-sensitivity trace metal ion detection method, comprising: modifying the precious metal surface using a DNA probe and modifying the quantum dot surface using a single-chain DNA probe; designing a single-chain DNA interposed with a RNA basic group as the substrate chain, and coupling the precious metal and the fluorophor; obtaining DNA enzyme with special activity to different metal using biology system evolution or vitro screening; precious metal generating quenching effect on the fluorescence generated by the fluorophor when the object precious metal ion is not present in the monitoring object and the obtained fluorescence intensity being very weak; the substrate chain of the DNA enzyme breaking at RNA basic group to result into the separation of the precious metal surface and the fluorophor when the precious metal ion specifically bonded with the DNA enzyme is present in the monitoring object, the quenching effect of the precious metal on the fluorescence diminishing and the read fluorescence intensity of the fluorophor increasing by magnitude order, therefore the high-sensitivity trace metal ion is monitored.