Heavy metal mercury detection method

The invention discloses a heavy metal mercury detection method. The method comprises the following steps: adding a solution to be detected to a reaction system containing nano-gold particles, papain and 2,6-dipicolinic acid, and quantitatively and qualitatively detecting the heavy metal mercury in the solution to be detected according to absorbance change detected through ultraviolet-visible absorption spectrum and change of the color in the reaction system. The reaction system is formed by the nano-gold particles, papain and 2,6-dipicolinic acid, the reactions system is combined with Hg through a covalent bond, and the heavy metal mercury is detected through whether red shift of the plasma resonance absorption peak of the surface of the nano-gold particles at 520nm occurs or not, so the method has the advantages of high sensitivity, good selectivity, rapidness and simplicity.