Aiming at the problems of low dye reduction rate and poor dyeing depth in the current electrochemical dyeing process, this paper reports on the use of iron salt solutions with different valence states as media to form a synergistic complexation system with sodium gluconate and Abal B ligand, to
achieve electrochemical reduction of the indigo dye. By controlling dyeing solution reduction potential, dye reduction rate, ferrous ion conversion rate, the effects of different iron salt media on the reduction effect of indigo dyes were studied. The effects of dye concentration, voltage and time on the performance of indirect electrochemical reduction system of indigo dye were investigated. The results show that the optimum process conditions were the concentration of indigo 2. 5 g/ L, ferrous sulfate 15 g/ L, sodium gluconate 12 g/ L, Abal B 10. 5 g/ L, sodium hydroxide 37. 5 g/ L, working voltage 10 V, and electrification time 40 min. Under these conditions, the reduction rate reached 89. 95%, the dyeing depth value of dyeing was improved by 4. 5% compared with that of traditional process. The color fastness of the two processes was found similar.