The invention discloses a process for fermenting soy sauce through biological enzymolysis. The process comprises the following steps: material selection, starter making, salt water preparation, fermented grains making, reflux pouring fermentation, leaching, preparation of product oil through blending and inspection, storage and delivery. The process has the beneficial effects that a false bottom, air holes, a pouring hole and a reflux hole are formed in a fermentation tank, so that either insulated fermentation or natural temperature fermentation can be carried out and the fermentation liquor can be automatically separated from the fermented grains and can undergo reflux pouring; by adopting the reflux pouring fermentation technology used in the fermentation tank and the biological enzymolysis technology, not only the burning phenomenon in the soy sauce fermented grains fermentation process can be effectively reduced, the bitter taste of the soy sauce can be eliminated and the soy sauce has lighter color, strong fragrance and gentle flavor, but also fermentation is thoroughly carried out, the soy sauce fermented grains are not sticky, the product yield is increased and the production cost is reduced; by adopting the advanced equipment, such as an inoculation mixing machine, a disk starter making machine and a sterilizer, the labor intensity is reduced, the production becomes more industrial, automatic and mechanical and the management becomes more scientific.