Abstract: Spring wheat plants (Triticum aestivum)were fumigated with ozone of low concentration (0.1ppm) for a long period of time in open-top chamber. With the increase in fumigation time, the content of chlorophyll in leaves decreased,the formation of malondialdehyde (MDA) and electrolyeic leakage increased linearly.Plants were exposed to ozone of various concentrations (0.2ppm, 0.3ppm and 0.4ppm) for a given time. The higher the ozone concentration became, the more rapidly the content of chlorophyll in leaves declined and the formation of MDA and the electrolyic leakage rose. As fumigated with ozone of low concentration or for a short time, the activity of superoxide dismutase (SOD) in leaves tended to increase; While high ozone concentration or long fumigation time caused a decrease of SOD activity. These results suggested that the matabolic disorder and various injury in leaves induced by ozone were the result of the increase of lipid peroxidation.