The traditional brewing process of soy sauce is based on soybean or soybean meal and other vegetable protein as the main raw material. After microbial fermentation, it produces a condiment that contains a variety of amino acids and has a special color, fragrance and taste. Scientists use soy protein isolate as raw material to study the application of soybean protein with different degrees of enzymatic hydrolysis in preparing soy sauce. First, the process parameters of enzymatic hydrolysis of soybean protein were determined through single-factor experiments, and then the quality of soy sauce with different enzymatic hydrolysis levels was studied. The results showed that the enzymatic hydrolysis temperature was 50℃, pH was 7.0, and the enzymatic hydrolysis time was 5. The proteolysis product of soybean separation under h conditions is most suitable for the preparation of soy sauce.