The utility model discloses an automatic quantification mechanism of saline water for a soy sauce fermentation tank. The mechanism comprises a flowmeter, a solenoid valve and a control circuit, wherein the flowmeter and the solenoid valve are installed on a saline water pipeline, the flowmeter is connected with the control circuit, and the solenoid valve is connected with the control circuit. Compared with the prior art, the automatic quantification mechanism has the advantages that automatic quantitative measurement is achieved, accuracy of flushed saline water volume is guaranteed, simultaneously, the manual operation can be reduced, and the labor cost can be saved.