Abstract: In the present work, corn peptides from zein were modified by D-glucosamine under transglutaminase to produce corn glycopeptides, and then the corn glycopeptides were fractionated sequentially using ultrafiltration membranes with molecular weight cut-off 5、3 and 1 ku, and four components with molecular weight >5, 3~5, 1~3 and <1 ku were obtained. The effect of molecular weight on the biological activities of corn glycopeptide was characterized by measuring the antioxidant and alcohol dehydrogenase activating activities of each molecular weight component. The results showed that the molecular weight distribution of the corn glycopeptides that had the ability to scavenge DPPH free radicals was in the range of 1~5 ku. At a concentration of 2 mg/mL, the corresponding activities were 83.22%, 59.39%, 2.248 and 37.92%, respectively. However, all corn glycopeptides components with molecular weight <5 ku had the activity of scavenging hydroxyl radicals, indicating that the biological activities of corn glycopeptides were greatly affected by the ultrafiltration membrane classification, and they could be selected according to the biological activities of corn glycopeptides.