Black bean soy sauce with a low-salt solid-state fermentation process was prepared by the black beans as raw material. Heilongjiang with green cotyledon was selected among different raw materials. Here, the best technique was determined. Firstly, the black beans were soaked for 4 hours under 121°, steamed for 15 min and mixed with the fried wheat (5:5, w/w). After inoculated with Aspergillus oryzae (0.4%, w/w) and cultured for 36 hours, the koji was obtained. When the brine (1:1, w/w) was added, soy sauce started to ferment. The content of total nitrogen, amino nitrogen, salt-free solids of the black bean soy sauce was even more than those of soy sauce derived from beans. Especially, the concentration of anthocyanins was 3.7g l^-1.