The invention discloses an acid mist purifying method in the electrolytic manganese leaching process, which comprises the steps of: (1) collecting acid mist, and delivering the acid mist to a purifying device through a pipeline; (2) purifying the acid mist in the purifying device; (3) delivering the acid mist to a spraying and neutralizing device and manganese-containing alkaline waste water to apart above or inside the spraying and neutralizing device through a pipeline, and neutralizing the manganese-containing alkaline waste water and CO2 gas in the acid mist; and (4) delivering the gas to a spraying and cooling device for cooling and steam removal, delivering the manganese-containing alkaline waste water to a part above or inside the spraying and cooling device through a pipeline, and spraying the manganese-containing alkaline waste water to carry out neutralization reaction with CO2 gas and sulfuric acid mist in the acid mist. The purifying method disclosed by the invention can prevent the acid mist from entering the atmosphere, fundamentally achieves the purpose of zero emission of acid mist, and avoids pollution of sulfuric acid mist to the environment; and the treatment and resource utilization of the manganese-containing alkaline waste water are realized, thus the manganese resource is saved; and the health of workers is effectively protected.