In this study, the degree of hydrolysis (DH) and polypeptide content were index optimization for corn gluten meal of hydrolysis process. Under the condition of pH 8.5, 60 ℃, orthogonal experiment to obtain the optimal combination for: amount of enzymeenzyme 3.5 g/100 g, hydrolysis time 2 h, solid-liquid ratio 1︰20 (g/mL); on this condition, the DH is 27.02%, peptide content is 85.23%. Meanwhile, optimized the decolorization technology, the best conditions: temperature 50 ℃, pH 3.5, activated carbon dosage: 1.5 g/100 mL, decoloring time 45 min; under the condition, corn peptide yield was 77.86%, the decolorization rate was 87.27%. After decoloring and desalination, three components were isolated by chromatographic separation. The result of hypoglycemic activity in vitro showed that CP1 had the better effect on promoting normal HepG2 cells’ glucose consumption, and the α-glycosidic enzyme inhibitory activity reached 34.64%, after RP-HPLC column purification, 14 components were gotten; the thirteenth (CP1-13) had the best α-glycosidic enzyme inhibitory activity, and reached 39.50%. Determined by UPLC-Q-TOF-MS/MS, the amino acid sequence was A-P-A-L-L-P-F.