Abstract: To rationally develop and utilize the procession of certain low-grade pyrolusite, the combination of more environmentally friendly and naturally macromolecular tannic acid, and acetic acid as a new composite green leaching agent was first investigated and applied in this experiment. It provides another sustainable and safe practice innovation for manganese leaching. The effects of acetic acid concentration, tannic acid concentration, liquid-solid ratio, reaction temperature, and reaction time on manganese leaching rate were studied through the single factor test and orthogonal test. The results showed that the main factors affecting manganese leaching rate were tannic acid concentration, acetic acid concentration, liquid-solid ratio, reaction time, and reaction temperature. Under the optimal process conditions (acetic acid concentration of 3.5 mol/L, tannic acid concentration of 25 g/L, liquid-solid ratio of 9 mL/g, reaction temperature of 85 ℃, and reaction time of 2.5 h), the leaching rate of manganese from pyrolusite could reach 97.26%.