Abstract: The manganese electrodeposition process faces problems such as low electrical efficiency, highly toxic SeO2 additives and difficult to control the deposition morphology. In order to obtain electro-deposited manganese with increased current efficiency and desired morphology as well as decreased addition of toxic SeO2 additive, , this paper prepared the MnSO4-(NH4)2SO4 electrolyte system according to the electrolytic manganese industry standard, and explored the effect of adding polyacrylic acid, glycine, ethylenediaminetetraacetic acid, gluconic acid and other auxiliary additives on manganese electrodeposition, so as to reduce the dosage of highly toxic main added SeO2 agent. The test method of constant current cathodic polarization curve, X-ray diffraction analysis, field emission scanning electron microscopy (SEM) and other characterization methods were used to study the relationship between cathodic electrochemical polarization behavior and manganese electrodeposition. The results showed that gluconic acid was the most suitable as a co-additive among the additives explored. When gluconic acid is used as an auxiliary additive and the amount of addition is 1.84 g L-1, the amount of toxic SeO2 can be reduced from 0.05~0.06 g·L-1 to 0.015 g·L-1, the current efficiency can be increased from 70% to 89.73%, and the energy consumption can be reduced from about 6500 kW·ht-1 to 4990.58 kW ht-1, and the product shape is dense and smooth to meet the needs. The research results will provide new ideas for green production and high-efficiency electrowinning in manganese electrolysis industry.