Abstract: The arsenic mass concentration in the biooxidation tailing solution generated by the biooxidation pretreatment of gold concentrates is still high after it is treated by one-stage neutralization in a biooxidation plant and if the solution is recycled,the biooxidation effect is influenced.Therefore,it is decided to use two-stage neutralization process for the treatment based on the study of principles of biooxidation tailing solution neutralization,and the operation conditions are optimized.Industrial application shows that the arsenic mass concentration in the neutralized solution generated in two-stage neutralization process is greatly reduced to about 0.30 mg/L and reaches the standards for national industrial wastewater discharge.Besides,the gold grade in the cyanidation tailings during the cyanidation leaching stage is reduced by 0.35 g/t.The gold recovery rate is increased by 1.2 percentage points.11.8 kg more gold can be recovered annually.The economic profits are great.