As a common technology for food processing, fermentation can maximize the nutritional value of food or increase the flavor of food. Soymilk is rich in plant protein, but plant protein is relatively difficult to be absorbed by the human body, the use of protease-producing strains to treat soy milk, can plant protein into peptides and amino acids, improve its digestion and absorption rate. The protease-active strains screened from traditional soybean fermented foods are more suitable for growth and reproduction with soybeans as a nutrient source, and the proteases produced are also more suitable for soy protein. The production process of traditional soybean paste in Northeast China is unique. It is generally fermented by steamed soybeans, which are prepared by multiple processes, such as stir-frying, brick making, fermentation, and sauce, with a long production history and unique flavor, and are traditional fermented foods in China. Because it is often brewed in a family, the types of fermentation microorganisms vary depending on the brewing environment. However, at present, the research on fermented bean paste is mostly focused on the research of Pixian bean paste. Many functional strains have been found in Pixian bean paste, including protease-producing strains. And these strains have been applied to the research and development of functional foods, such as descending amines and inhibiting the growth of Aspergillus flavus. Analogous to the study of Pixian bean paste, the experiment took Fushun farmhouse soybean paste as the research object, and screened the protease strains in northeast soybean paste through the hydrolysis circle, and obtained 8 strains with good decomposition of soybean protein, which were identified by morphological observation and 16S rDNA sequencing as Bacillus, including 1 strain of Bacillus zhangzhouensis, 1 strain of Bacillus velezensis, 2 strains of Bacillus subtilis, 1 strain of Bacillus siamensis, 2 strain of Bacillus methylotrophicus, 1 strain of Bacillus tequilensis. After the safety analysis of the screened strains determined the safety of the strains, the strains were used for soy milk fermentation, and the soluble peptide content, amino peptide content, hydrolysis degree and sensory evaluation of soy milk before and after fermentation were determined. The results showed that the soluble peptide content of soy milk increased significantly, and the effect of soy milk after treatment with BJ-20 was the most significant, with an increase of 37.23%. In addition, the amino peptide nitrogen and hydrolysis degree of soy milk also changed significantly, among which the effect of soy milk treated with BJ-6 was the most significant, with aminopeptide nitrogen increasing by 10.87% and the hydrolysis degree being 23.49%. The sensory evaluation results showed that the tissue state of soy milk was significantly improved after treatment. The results of this study enrich the repertoire of bean processing cultures, increase the diversity of soybean products, and provide reference and theoretical support for the development of soybean health function.