The glycated grass carp (Ctenopharyngodon idella) scale gelatin was tested in vitro simulated gastrointestinal digestion to study the antioxidant properties of enzymatic hydrolysis peptides. In the process of gastric digestion, the scavenging capacity of DPPH· and ·OH first increased and then decreased, while the Fe2+ chelating ability first decreased and then increased. In the process of gastrointestinal digestion, DPPH· scavenging ability increased to a stable value, while ·OH scavenging ability of glycation products were less than non-glycated fish scale gelatin. In addition, Fe2+ chelating ability showed inconspicuous change. When the glycation reaction time extended, the degree of glycation increased gradually, and glycation reaction reduces the digestive properties of fish scale gelatin in the gastrointestinal tract. In addition, the glycation reaction can reduce the digestive activity of fish gelatin in gastrointestinal and affect the anti-oxidant activities of its digestions.