The rapid development of industry in the world has brought serious negative effects, so pollution control and prevention is an important issue for the future environment. The discharge and treatment of metal ions in water environment are becoming more and more serious. Common heavy metal analysis methods need the support of large-scale instruments. In the study, the differently control of wavelength, temperature and concentration. Explore theoretical analysis solutions based on laser absorption and scattering, Design of metal ion analysis of laser light penetration. The influence of medium change of metal ions on the light dispersion path is measured by direct light. Preliminary results found that the 532nm wavelength laser light has a deviation in the determination of metal ions. Laser wave was analysed by water diffusion chromatography. In order to facilitate the change from large equipment to portable metal ion detection technology.