Abstract: Thiosulphate gold leaching is a kind of cyanide-free leaching method with application prospect. Compared with the traditional cyanide method, it has the advantages of short leaching time, fast leaching rate, low toxicity and environmental protection. Based on the complexity of thiosulfate gold leaching system, the electrochemical behavior of thiosulfate gold leaching in copper ammonia/amine system and the interaction mode between thiosulfate, copper/copper ammonia complex ion and ammonia/amine in the gold leaching process were discussed.