The leaching of manganese from manganese dioxide ores in sulfuric acid solution was investigated. The effects of agitation, sulfuric acid concentration and solid/liquid mass ratio on the leaching efficiency of manganese were studied. In this study, manganese dioxide ores were treated by reduction roasting using charcoal as a reductant at 700 oC for 120 min. Then, roasted samples were subjected to extract manganese by sulfuric acid leaching. in each leaching test, 75 g of sample was put and leached in a glass reactor with 750 mL sulfuric acid solution. At the end of each leaching experiment, the slurry was filtered and filtrate was analyzed by Atomic Absorption Spectrometer. The experimental results indicated that the leaching rate increases with the increases of the agitation, sulfuric acid concentration and with the decreases of solid/liquid mass ratio. The optimal condition for leaching manganese from manganese dioxide ores was determined as the agitation of 400 rpm and sulfuric acid concentration of 12% for 180 min at 75 oC. Under the optimal condition, the leaching efficiency of manganese can reach 84.61%.