The invention provides a making method of pure breed fermented soybean sour soup. The method comprises the following steps: collecting raw materials, filtering adding auxiliary materials, sterilizing,inoculating, fermenting, filtering and disinfecting to obtain the soybean sour soup. The invention provides the making method of the soybean sour soup; the obtained soybean sour soup is short in fermentation period, high in acid yield, and very rich in contents of flavor substances and characteristic nutrients; furthermore, the making method effectively solves the problem of wastewater treatmentin a bean curd production process, and is in line with the current green and sustainable development concept; the bean product industry is organically combined with the sour soup industry, so that thedevelopment of the bean product industry and the sour soup industry is better promoted.