Method for rapidly detecting concentration of heavy metal ions in water sample by using gel

The invention discloses a method for rapidly detecting the concentration of heavy metal ions in a water sample by using gel. The method comprises the following steps: mixing sulfydryl-containing L-cysteine, water and 0.8% agar solution in proportion to form 1mL of solution, adding the 1mL of solution into a small glass bottle with the volume of 2mL, and cooling to form a colorless transparent gel substrate; adding 0.3 mL of a to-be-detected water sample to the upper part, sealing the bottle with a bottle cap, putting the bottle into a metal bath, incubating the solution, and taking outthe bottle; and sucking an upper-layer solution, adding a HAuCl4 solution, sealing the bottle, putting the bottle into the metal bath, incubating the solution, and taking out the solution, wherein a color band with obvious color on the upper layer of the gel, and compared with the color band formed without adding the Hg (II), if the color is consistent, proving that the water body does not contain the Hg (II) or the content of t