In this study， soybean meal was used as a raw material to investigate the differences in yield of soybean meal peptides from neutral protease， complex flavor protease， papain， trypsin， and pepsin. The preparation process was optimized by the single factor test and the response surface test. The outcome showed that the compound flavor protease was used as the enzymatic hydrolyzing enzyme， the enzymatic hydrolysis temperature was 50 ℃， the enzymatic hydrolysis pH was 6.5， the enzymatic hydrolysis time was 7 h， the amount of enzyme added was 1%， and the substrate concentration was 4 g/100 mL. Under these conditions， the yield of polypeptides could reach（12.42±0.06）%. And the soybean meal peptides had better textures. The results of this study provide a good foundation for the utilization of soybean protein and further application of functional peptides．