A method using hydrogen peroxide to eliminating DTT interference during the nucleic acid isothermal amplification detection of mercury ions comprises: a primer containing a false priming site and initiating nucleic acid isothermal amplification and a template recognition sequence are subjected to isochoric mixing according to the concentration 100 nM, and the recognition sequence is combined with mercury ions in a to-be-measured mercury-containing solution to form a stable hybridization structure capable of being recognized by a polymerase; the stable hybridization structure is subjected to a hybrid reaction with a hydrogen peroxide solution, an amplification substrate, a DNA polymerase KF, SYBR Green I and an amplification reaction buffer, an amplification reaction is initiated under the action of the polymerase, and a double-stranded DNA is generated; SYBR Green I can be specifically bound on the double-stranded DNA molecule, and send out a fluorescence signal at the same time; the sequence after the amplification is represented by a solubility curve and AGE (agarose gel electrophoresis), and the process proves that hydrogen peroxide eliminates DTT interference. The method can be used for eliminating DTT interference on the detection of trace mercury ions, the system compatibility is good, and the operation is simple and convenient and does not depend on complicated equipment.