This study examined the biochemical responses of wheat(Triticum aestivum)to the stress of rare earth yttrium(Y)and showed that 25–100 mg/kg Y treatments evidently increased the biomass(root mass,shoot mass and leaf mass),accompanied by a significant(p<0.05)increase in the chlorophyll(CHL)content in wheat leaves.Increased malondialdehyde(MDA)levels were detected in wheat shoots(stem and leaf)and roots too,indicating the presence of poisoning active oxygen species(AOS).The MDA content in wheat roots increased with the augmentation of Y concentration.These results indicated that there was a dose-dependent effect of Y on the changes of MDA content in wheat roots.Although the activities of superoxide dismutases(SOD),peroxidases(POD)and catalases(CAT)in wheat shoots and roots irregularly fluctuated with the increase in Y concentration,25–100 mg/kg Y significantly(p<0.01)increased the activities of SOD and POD.In general,the dose-dependent effects of Y on the activity of antioxidant enzymes were insignificant.Our data also indicated that the increase in SOD and POD activities could be used as a good biomarker for the stress induced by low concentrations of Y. This study examined the biochemical responses of wheat (Triticum aestivum) to the stress of rare earth yttrium (Y) and showed that 25-100 mg / kg Y treatments evidently increased the biomass (root mass, shoot mass and leaf mass), accompanied by Significantly (p <0.05) increase in the chlorophyll (CHL) content in wheat leaves. Increased malondialdehyde (MDA) levels were detected in wheat shoots (stem and leaf) and roots too, indicating the presence of poisoning active oxygen species (AOS) The MDA content in wheat roots increased with the augmentation of Y concentration. These results indicated that there was a dose-dependent effect of Y on the changes of MDA content in wheat roots.Although the activities of superoxide dismutases (SOD), peroxidases ( POD) and catalases (CAT) in wheat shoots and roots irregularly fluctuated with the increase in Y concentration, 25-100 mg / kg Y significantly (p <0.01) increased the activities of SOD and POD. General, the dose- of Y on the activity of antioxidant enzym es were insignificant. Our data also indicated that the increase in SOD and POD activities could be used as a good biomarker for the stress induced by low concentrations of Y.