The invention provides a heavy metal detection method. The method comprises steps as follows: different voltage values are provided by an electrode enrichment reaction, a pure aluminum sheet which is5 cm long and 1 cm wide is selected as a negative electrode of a power supply, a platinum wire electrode is taken as a positive electrode, and a reference electrode is added; an electrochemical workstation supplies electrons to the negative electrode in the electrode enrichment process, and under the action of an electric field, heavy metal positive ions in the solution can be gathered together towards the negative electrode, electrons are obtained, and positive ions are converted into elementary substances and attached to the surface of a cathode material; a uniform heavy metal attaching film, namely, an object for LIBS (laser-induced breakdown spectroscopy) laser ablation, is formed on the surface of the aluminum sheet in the solution, and a sample is obtained after the film is dried for5 min; the sample surface is subjected to laser ablation by a laser, substances on the surface are gasified instantaneously, a plasma signal is produced, plasma emits a characteristic spectrum of elements in the evolution process, and elementary composition and content of the sample can be correspondingly obtained by analyzing information such as wavelength, strength and the like of spectral lines.