Abstract: In this paper, Acer truncatum seed meal was hydrolyzed by alkaline protease method. The enzymatic hydrolysis time, enzyme dosage, pH, enzymatic hydrolysis temperature and solid-liquid ratio were investigated, and the yield of enzymatic hydrolysis polypeptide was taken as the evaluation index. On the basis of the single-factor experiments and the Box-Behnken central combination experimental design, the preparation process of alkaline protease hydrolyzed polypeptide of Acer truncatum seed meal was optimized. The amino acid composition, water absorption, oil absorption, foaming, emulsifying and surface hydrophobicity of the enzymatic hydrolyzed peptides were characterized. The results showed that the optimal enzymatic hydrolysis process was as follows: enzymatic hydrolysis time 3.3 h, pH10, enzyme dosage 3%, enzymatic hydrolysis temperature 55 ℃. Under the optimum preparation conditions, the yield of peptides hydrolyzed by alkaline protease from Acer truncatum seed meal was 40.13%±0.15%. The analysis of amino acid composition showed that the amount of eight essential amino acids contained in the enzymatic hydrolysis polypeptide was as high as 20.3%, which was much higher than the amount of essential amino acids recommended by FAO. In addition, the oil absorption of enzymatic hydrolysis polypeptide (4.553 g/g) was higher than that of soybean protein (2.61 g/g), its surface hydrophobicity (1365.3) was similar to that of soybean 7S globulin, and its emulsifying property and emulsifying stability were slightly lower than that of soybean protein isolate. The alkaline protease hydrolyzed polypeptide of Acer truncatum seed meal obtained in this study had good functional characteristics, which also showed that it could be used as a potential functional component in food, providing data and theoretical support for the new application and development of Acer truncatum seed meal.