Abstract: We used maize and sorghum seedings as the material to investigate the protective effects of phosphate buffer on improving resistance and decreasing injury of sulphurous acid from membrane lipid peroxidation.The results showed that the activities of superoxide dismuiase (SOD) increased, the contents of superoxide anion radical (O₂^-?) and malondialdehyde(MDA) decreased, the levels of electrolytic leakages decreased, and the seedings resistance improved. After treated with the different concentration of sulphurous acid,the seedings sprayed with phosphate buffer were less harmed than not-sprayed. The protective effects were obvious and varied with the concentration of sulphurous acid and plant species. The effect on sorghum was higher than that on maize.