Metal ion stress results in a variety of physiological damage to plants, including membrane lipid peroxidation. The effects of different metal ions on the membrane lipid peroxidation are various, and so far, the little knowledge about the relationship between lipid peroxidation and characteristics of metal ions is known. The physical and chemical effects of metal ions on the anions and other moleculars depend on the polarization of metal ions, such as the amount of charge, radius and electron shell structure. In this study, the stresses caused by metal ions with different ionic polarization on hydroponic Arabidopsis thaliana and Brassica napus seedings were investigated, and the production of Malondialdehyde (MDA) of both plants incubated to different metal ions for 1, 3 and 5 days were tested. The results indicated that with the same concentration treatment, Li+ induced more production of MDA than that of Na+ and K+, Fe3+ induced more production than that of Fe2+, and Fe2+ induced more production than that of Ca2+.That is, with the same amount of metal ions, the smaller ion radius, higher ion potential and more complicated electronic shell, the more MDA were produced in plants. The results suggested that there was positive relationship between the ability of inducing MDA production and the ionic polarization, that is, the higher charge, smaller ionic radius and more complex the electron shell, the more severe oxidative stress were induced.