Abstract: The ameliorating effects of organic acids (oxalic acid, ethanoic acid and citric acid) on lead stress were studied by analysis the physiological characteristic of wheat seedling. The results showed that three organic acids could ameliorate the destroy of lead on chlorophyll; Low concentration of organic acid could enhance the activities of protective enzyme (SOD, CAT and POD), decrease the content of MDA, but with the increasing of organic acid concentration, had no apparent ameliorating effects, the activities of protective enzyme decrease, the content of MDA increase; The ameliorating effect of oxalic acid was most apparent.