Abstract: In the beneficiation and smelting process,mercury in the ore undergoes transformations in its state of occurrence and chemical phase,existing in various forms such as elemental mercury and mercury ions throughout the process.Through process investigation and phase analysis,the transformation process of mercury in the entire beneficiation and smelting process is revealed.In the stages of crushing and grinding,flotation,and bio-oxidation,mercury mainly exists in the form of cinnabar in the solid phase of the ore.Upon entering the CIL stage,mercury undergoes solid-liquid phase migration.Mercury and mercury salts react with cyanide to form mercury cyanide complexes,leading to an increase in sodium cyanide consumption.Furthermore,activated carbon easily adsorbs the mercury cyanide complexes in the solution,resulting in mercury poisoning of the activated carbon and a decrease in the gold recovery rate.In response to the impact of mercury on gold recovery rate and environmental hazards,countermeasures are proposed to provide technical references for similar enterprises.