Abstract: Gold has important strategic significance and economic value.At present,cyanidation is mainly used to extract gold in the industry.However,cyanidation has a long production cycle and the cyanide used is highly toxic.If it is not well managed,there will be potential environmental pollution risks.Taking the gold-bearing acid residue of a gold smelter as the research object,the leaching of gold in a thiourea system was studied.The results show that the leaching rate of gold from gold-bearing acid residue is only 83.17 % under the condition of conventional intensified stirring thiourea leaching.Under the condition of ultra-fine grinding to enhance thiourea leaching,the gold leaching rate of gold-bearing acid residue reaches 89 %;it is recommended that the best experimental scheme is enhanced stirring leaching＋one stage ultra-fine grinding leaching＋two stage ultra-fine grinding leaching for three times＋enhanced stirring leaching.The leaching rate of gold from gold-bearing acid residue can reach 95.04 %,which can realize the clean and deep extraction of gold from gold-bearing acid residue and provide theoretical and technical support for the industrial application of the non-cyanide gold extraction process.