The invention discloses a production method of high-purity manganese sulfate. The method includes the following steps that 1, sodium sulfide is added into a by-product produced after cobalt smelting,and a first intermediate is prepared through a stirring reaction and separating precipitation; 2, manganese sulfate crystals are added into the first intermediate, and a second intermediate is prepared through a stirring reaction and separating precipitation; 3, sodium fluoride is added into the second intermediate, a third intermediate is prepared through a stirring reaction and separating precipitation; 4, a P507 loaded organic extraction agent is used for extracting the third intermediate, and a manganese sulfate solution is prepared; 5, the manganese sulfate solution is crystallized, filtered, centrifugally dehydrated and dried to obtain high-purity manganese sulfate. The invention further discloses a production device for the high-purity manganese sulfate. Recycling of valuable metalsin cobalt ore is achieved; a two-step calcium removal method is used, most of calcium is removed by using the micro-solubility of calcium sulfate in the first step, and a small amount of sodium fluoride is used for deep calcium removal in the second step.